Defect-free Y2O3 transparent ceramics is an interesting material which is used for IR windows, nozzles or laser host, etc, due to its mechanical and optical properties, high thermal and chemical stability, and high melting point. To achieve full densification and the absence of pores, sintering aids are used. For yttria ceramics, the optimal choice is ZrO2. It has a significant influence not only on transmittance, but on the other characteri-stics of the material as well. For high transparency, ceramics has to remain single-phase, thus forming a solid solution of Y2O3 and ZrO2, but the solubility limit isn't studied in detail. Therefore, the presented work aims to investigate the solubility limit of ZrO2 in yttria ceramics and the dependence of properties on the concentration of sintering aid. Ceramics samples with a concentration of ZrO2 of 0-11 mol% were obtained by uniaxial and cold isostatic pressing (CIP) followed by vacuum sintering at 1735 °C for 22 h. The SEM and XRD analysis, refractive index and transmittance measurements were performed. No secondary phases were observed in analysed samples by SEM, which indicates the formation of a solid solution and full solubility of ZrO2 in the analysed range of concentration. Also, it was found that even 3 mol% of ZrO2 significantly improve the microstructure of samples. It allows for the elimination of residual porosity due to full densification during sintering. Also, the grain size decreased from 14 ?m for pure Y2O3 to 3.8-6.1 ?m for samples with 3-11 mol% of ZrO2. XRD analysis showed that the phase composition did not change between samples with 0 and 11 mol% of sintering aid. Decreasing of lattice parameters with increasing of ZrO2 amount was observed due to the replacement of Y3+ ions in the lattice by the smaller Zr4+. A steady increase of refractive index was observed with increasing Zr content. Obtained results allow us to conclude, that the solubility limit of ZrO2 in Y2O3 was not reached within the studied range and that the presence of ZrO2 improves ceramics properties. In the next step, optical transmittance was analysed. Among all obtained Y2O3:Zr4+ ceramics the highest transmittance (78.60% at 1100 nm at a thickness of 2.11 mm) was achieved for the sample with 7 mol.% of ZrO2.

Five porcelain and porcelain stoneware bodies were investigated to compare sintering mechanisms and kinetics, phase and microstructure evolution, and high temperature stability. All batches were designed with the same raw materials and processing conditions, and characterized by optical dilatometry, XRF, XRPD-Rietveld, FEG-SEM and technological properties. Porcelain and porcelain stoneware behave distinctly during sintering, with the convolution of completely different phase evolution and melt composition/structure. The firing behavior of porcelain is essentially controlled by microstructural features. Changes in mullitization create conditions for a relatively fast densification rate at lower temperature (depolymerized melt, lower solid load) then to contrast deformations at high temperature (enhanced effective viscosity by increasing solid load, mullite aspect ratio, and melt polymerization). In porcelain stoneware, the sintering behavior is basically governed by physical and chemical properties of the melt, which depend on the stability of quartz and mullite at high temperature. A buffering effect ensures adequate effective viscosity to counteract deformation, either by preserving a sufficient skeleton or by increasing melt viscosity if quartz is melted. When a large amount of soda-lime glass is used, no buffering effect occurs with melting of feldspars, as both solid load and melt viscosity decrease. In this batch, the persistence of a feldspathic skeleton plays a key role to control pyroplasticity.

Transparent yttrium aluminum garnet (YAG) ceramics are mostly sintered under vacuum to favor pore closure. However, this may conceal the origin of microstructural defects, complicating process optimization. We describe a useful approach to understand the origin of defects in transparent YAG ceramics: reactive sintering was performed in air at a moderate temperature for a short time. The resulting microstructure allowed to understand the origin of defects in corresponding vacuum-sintered specimens. The porosity of air sintered samples could be related to the presence of aggregates of starting oxide particles, which eventually under vacuum react to form YAG, but leave behind pores

During the various stages of ceramic tile production, sintering kinetics, phase transformations and variation of the main properties of non-crystalline matrix are considered the major parameters to be kept under control. Particularly, during the sintering process a complex evolution of both phase composition and chemistry of the liquid phase occurs, according to the dynamic equilibrium established between the residual minerals and the new crystalline phases formed during firing. This contribution aimed at comparing the evolution of phase composition and of non-crystalline matrix properties during the vitrification path of four representative industrial ceramic formulations (soft porcelain, vitreous china; two different batches of porcelain stoneware, including a glass-bearing one). These batches were designed and prepared at the laboratory scale, simulating the industrial ceramic process. The sintering kinetics of each sample was determined under isothermal conditions through an industrial-like firing schedule by optical thermo-dilatometric analysis. Samples were investigated between the temperature at which the viscous flow sintering starts (around 1000°C) up to the onset of deformation (up to 1400°C for porcelain), upon increasing dwell time. The phase composition was assessed by the Rietveld refinement and the chemical composition of the vitreous phase was obtained by subtracting the contribution of each mineralogical phase, considering its stoichiometric ideal formula. The melt properties were estimated by predictive models based on the chemical composition of the liquid phase. An increasingly faster sintering kinetics was observed in the order: soft porcelain, vitreous china, porcelain stoneware, glass-bearing stoneware. Different vitrification paths were observed with a correlation between the dissolution kinetics of feldspar and quartz. Remarkable differences were observed in those samples where mullite occurred as primary or secondary mullite. Those differences clearly reflected a distinctive evolution of chemical features and glass network connectivity parameters of the non-crystalline matrix. The porcelain stoneware sintered by fast cycles thanks to a sort of buffering effect played by quartz and primary mullite melting rates. In contrast, vitreous china and soft porcelain needed higher temperature and/or prolonged time to activate both the growth of secondary mullite and the contemporaneous quartz dissolution, and the variation of properties of the noncrystalline matrix.

The localization of the rubber vulcanization reaction close to the silica filler surface was investigated in isoprene rubber composites (IR NCs): the main goal was to highlight the role of curing agents' dispersion and filler surface features on the spatial propagation of the rubber cross-links and the resulting mechanical behavior of the ma- terial. The study was realized by tailoring the morphology of the curing activator, i.e. by vulcanizing IR NCs with Zn@SiO2 double function filler, composed of Zn(II) single sites anchored on SiO2 filler, in comparison to silica filled IR NCs vulcanized with microcrystalline ZnO . The microscopic cross-links distribution was measured by Transmission Electron Microscopy for network visualization (NVTEM) and Time Domain Nuclear Magnetic Resonance (TD-NMR). Besides the NCs mechanical behavior was characterized both at small strain and at fracture. In the presence of Zn@SiO2, higher cross-link density in proximity to SiO2 particles was evidenced, which gradually spreads from the filler surface to the bulk, induced by localization of the Zn(II) centers. IR NCs with Zn@SiO2 resulted stiffer (+45%) and with a lower fracture toughness (less than one third), compared to m- ZnO based NCs, which shows a quite homogeneous structure of the rubber cross-links network. The results highlighted the correlation between the composites structural features and their macroscopic behavior, paving the way to modulating the mechanical properties of elastomeric materials by tuning the nature of the curing agents.

The present work explores the feasibility of joining the CoCuFeMnNi high entropy alloy by laser beam welding. An appropriate feasibility window is identified, and the optimal process parameters (300 W power, scanning speed 20 mm s-1, spot size 0.45 mm) are related to the properties of the studied material. Cu's tendency to segregate from other alloying elements is found to dominate the microstructural evolution: the welding process induced the formation of Cu-rich second phases within the melted zone (MZ), as interdendritic phase, as well as in the heat-affected zone (HAZ) as grain boundary phase. Mechanical resistance of the welded beads and the HAZs was improved (187 HV on average) over one of the base materials (BMs) (160 HV on average) owing to the formation of Cu-rich phases and solidification stresses. Consequently, tensile strength (576.4 MPa) and elongation to failure (28.3%) are almost the same as in the BM. Indeed, failure during tensile tests always took place outside the welded bead, therefore confirming the extreme soundness of the performed laser beam welding. Such results confirm that laser welding may be safely applied to relatively complex high entropy alloys (HEA), thus easing their practical application. © 2022 The Authors. Advanced Engineering Materials published by Wiley-VCH GmbH.

Total joint arthroplasty bearings, which are most typically implanted in the human hip and knee, are composed of ultra high molecular weight polyethylene (UHMWPE). However, the bioactivity and mechanical performance of this polymer need improvement and several efforts have been made with this regard, in order to extend the material's service life and expand its biomedical applications.In this study, two distinct procedures for producing UHMWPE composites with varying cellulose nanocrystal loadings were used (CNCs). The microstructure, mechanical, and electrical properties of the resultant material were all thoughtfullyexamined.The research shows that by varying the concentration of CNCs and modifying the preparation procedures, it is possible to drastically alter the morphologies of composites and, as a result, their mechanical and electrical properties. Besides, the electrical measurements can be used as useful tool for studying the reproducibility of the manufacturing process

In materials science, a detailed study of the microstructural characteristics, from the micro- down to the nano-scale, is fundamental for the identification of particular features, deriving from processing, which are responsible of specific thermo-mechanical behaviors. Only with an overall understanding of the microstructure evolution and behavior under extreme environment, corrective actions can be taken and materials performance ameliorated beyond current state of art. Extreme environment has a broad meaning, that might imply high-speed rate impact, corrosion, high temperature and ablation or a combination thereof. Here, the focus is on those structural ceramic materials that must withstand high thermo-mechanical loads at temperature above 1500°C. Thinking about the fields of machining and mining, WC-based ceramics play a major role, but are rarely used above 1000-1200°C due to the common addition of metallic phases. Moving then to the aero-space and hypersonic fields, the family of materials known as ultra-high temperature ceramics (UHTC) is the most suitable candidate. Each of the identified environment imposes a set of different structural requirements that are achievable only upon a careful tailoring of components, synthesis and processing. A series of ceramics and their unique microstructural features are presented and correlated to the observed specific properties.

The synthesis of functionalized polyolefins through coordination-insertion polymerization is a highly challenging reaction. The ideal catalyst, in addition to showing a high productivity, has to be able to control the copolymer microstructure and, in particular, the way of the polar vinyl monomer incorporation. In this contribution, we modified the typical Brookhart's catalyst by introducing in the fourth coordination site of palladium a hemilabile, potentially bidentate ligand, such as a thiophenimine (N-S). The obtained cationic Pd(II) complexes, [Pd(Me)(N-N)(N-S)][PF6], generated active catalysts for the ethylene/methyl acrylate (MA) copolymerization leading to the desired copolymer with a different incorporation of the polar monomer depending on both the reaction medium and the N-S ligand. Surprisingly enough, the produced copolymers have the inserted acrylate both at the end of the branches (T(MA)) and in the main chain (M(MA)) in a ratio M(MA)/T(MA) that goes from 9:91 to 45:55 moving from dichloromethane to trifluoroethanol (TFE) as a solvent for the catalysis and varying the N-S ligand. The catalytic behavior of the new complexes was compared to that of the parent compound [Pd(Me)(N-N)(MeCN)][PF6], highlighting the fact that when the copolymerization is carried out in trifluoroethanol, this complex is also able to produce the E/MA copolymer with MA inserted both in the main chain and at the end of the branches. Accurate NMR studies on the reactivity of the precatalyst [Pd(Me)(N-N)(MeCN)][PF6] with the two comonomers allowed us to discover that in the fluorinated solvent, the catalyst resting state is an open-chain intermediate having both the organic fragment, originated from the migratory insertion of MA into the Pd-Me bond, and the acetonitrile coordinated to palladium and not the six-membered palladacycle typically observed for the Pd-?-diimine catalysts. This discovery is also supported by both DFT calculations and in situ NMR studies carried out on [Pd(Me)(N-N)(N-S)][PF6] complexes that point out that N-S remains in the palladium coordination sphere during catalysis. The open-chain intermediate is responsible for the growth of the copolymer chain with the polar monomer inserted into the main chain.

A comprehensive, bottoms-up characterization of two of the most widely used biomedical Ti-containing alloys, NiTi and ?-Ti, was carried out applying a novel combination of neutron diffraction, neutron prompt-gamma activation, surface morphology, thermal analysis and mechanical tests, to relate composition, microstructure and physical-chemical-mechanical properties to unknown processing history. The commercial specimens studied are rectangular (0.43 × 0.64 mm~0.017 × 0.025 inch) wires, in both pre-formed U-shape and straight extended form. Practical performance was quantitatively linked to the influence of alloying elements, microstructure and thermo-mechanical processing. Results demonstrated that the microstructure and phase composition of ?-Ti strongly depended on the composition, phase-stabilizing elements in particular, in that the 10.2 wt.% Mo content in Azdent resulted in 41.2% ? phase, while Ormco with 11.6 wt.% Mo contained only ? phase. Although the existence of ? phase is probable in the meta-stable alloy, the ? phase has never been quantified before. Further, the phase transformation behavior of NiTi directly arose from the microstructure, whilst being highly influenced by thermo-mechanical history. A strong correlation (r = 0.878) was established between phase transformation temperature and the force levels observed in bending test at body temperature, reconfirming that structure determines performance, while also being highly influenced by thermo-mechanical history. The novel methodology described is evidenced as generating a predictive profile of the eventual biomechanical properties and practical performance of the commercial materials. Overall, the work encompasses a reproducible and comprehensive approach expected to aid in future optimization and rational design of devices of metallic origin.

Advanced ceramic materials are the most appropriate to find application in extreme environments in view of their exceptional combination of unordinary properties. The definition of extreme environment is very broad, but in the field of materials science it can be summarized as the set of applications in which materials with properties bordering on what is currently available are required. It was decided to divide the possible applications on the basis of the thermal regime: low, medium, and high, as the requirements that the materials must satisfy are completely different. With regard to the low temperature regime, B4C-TiB2 composites for ballistic applications, such as body armors, have been studied due to their lightness, impact resistance and high hardness. The influence of the processing and of small WC additions on the microstructure has been thoroughly analyzed to ultimately correlate a set of mechanical properties to the fine and overall microstructure assembly. The dense ceramics were typified by development of a core/shell structure of the boride grains, with the shell comprising a (Ti,W)B2 solid solution with d variable amount of W guest cation depending on the processing route. The concentrations of tungsten in the solid solution have been correlated to nano-hardness and hence to the theoretical strength by means of a series of nanoindentations and explained an increased plastic behavior for high W substitutions, beneficial to retain fracture strength. Then, moving to the intermediate temperature regime, encountered especially by cutting tools for applications such as mining and machining, even in corrosive environments like sea waters, in which, in addition to the high hardness, resistance to wear and corrosion are required, a binderless tungsten carbide ceramic containing 5 vol% silicon carbide was hot pressed to full density at 1820°C. The formation of a transient W-C-Si-O liquid which facilitated the oxide removal at relatively low temperature, was conducive to the development of a microstructure with bimodal grain size in the form of polygons or rods. This microstructural asset led to outstanding mechanical properties from room to elevated temperature. For the first time, WC-materials displayed strength over 1 GPa up to 1500°C and fracture toughness from 7 to 15 MPa??m. Subsequently, materials for the high- and ultra-high temperature regime were studied, as possible candidate materials for aerospace applications, such as hypersonic aircraft nozzles in which materials with high melting temperature, resistance to ablation and damage coupled with a relatively low density are of vital importance. The most suitable materials are the ultra-high temperature ceramics (UHTCs), including borides and carbides of the transition metals in group IV and V. The core-shell structures formed upon addition of an external guest cation in the boride matrix were studied in depth using both SEM and TEM. These structures revealed the precipitation of nano-inclusions of different nature, size and shape depending on the added cation, which were partially responsible for improvements in the mechanical properties of the ceramics especially in the high-temperature range. This finding represents a starting point towards the production of new hierarchical nanocomposites for extreme environment and a first step towards the understanding of the incredible properties of high entropy ceramics. In order to reduce the density of bulk UHTCs below 6 g/cm3, the addition of TiB2 to a ZrB2 matrix was studied. The further addition equal to 5% of third compound containing Hf, V, Nb, Cr was introduced in order to overcome the poorer oxidation resistance that characterizes the TiB2 phase. In this way solid solutions with three elements have been obtained. They have been investigated from the microstructural point of view and, from these first preliminary analyses, have shown a different formation behavior as compared to the simple binary solutions. The last part of this dissertation is focused on the microstructural characterization of a recently born class of materials, known as ultra-high temperature ceramic matrix composites (UHTCMCs ) obtained by slurry infiltration or reactive melt infiltration to understand: 1) the role of Y2O3 during densification, on the microstructure evolution and on the mechanical properties of a slurry infiltrated carbon fiber preform by a ZrB2-SiC slurry; 2) the mechanism of formation of the particular microstructure resulted from reactive infiltration and low temperature sintering of a ZrB2-Zr2Cu-B mixture in to a Cf preform.

Densification behavior, microstructure, and mechanical properties of zirconium diboride (ZrB2) ceramics modified with a complex Zr/Si/O-based additive were studied. ZrB2 ceramics with 5-20 vol.% additions of Zr/Si/O-based additive were densified to >95% relative density at temperatures as low as 1400 degrees C by hot-pressing. Improved densification behavior of ZrB2 was observed with increasing additive content. The most effective additive amount for densification was 20 vol.%, hot-pressed at 1400 degrees C (similar to 98% relative density). Microstructural analysis revealed up to 7 vol.% of residual second phases in the final ceramics. Improved densification behavior was attributed to ductility of the silicide phase, liquid phase formation at the hot-pressing temperatures, silicon wetting of ZrB2 particles, and reactions of surface oxides. Room temperature strength ranged from 390 to 750 MPa and elastic modulus ranged from 440 to 490 GPa. Vickers hardness ranged from 15 to 16 GPa, and indentation fracture toughness was between 4.0 and 4.3 MPa center dot m(1/2). The most effective additive amount was 7.5 vol.%, which resulted in high relative density after hot-pressing at 1600 degrees C and the best combination of mechanical properties.

We present here an investigation aimed at exploring the role of the microstructure on the magnetic properties of nanostructured cobalt ferrite. Bulk, almost fully dense, nanograined ferrites have been obtained starting from nanopowders prepared by a simple, inexpensive, water-based, modified Pechini method. This synthesis yielded largely aggregated, pure single-phase cobalt ferrite nanoparticles of ca. 35 nm average size, which have been then densified by high-pressure field-assisted sintering. Different sintering conditions (pressure up to 650 MPa and temperature up to 800 °C) and procedures have been used on both as-prepared and milled nanopowders in order to obtain materials with a spectrum of complex microstructures. In all cases, the sintering process did not produce any change in the phase composition. At the same time, using a high uniaxial pressure in combination with relatively low sintering temperatures and times, allowed for obtaining a high degree of densification while preserving the nanometric size of the crystallites. Moreover, we observed that in the densified materials the best magnetic properties are not necessarily associated with a more uniform microstructure, but rather arise from a delicate balance between moderate aggregation, grain size and high density.

High temperatures affecting buildings during fires have a potential of impact on the material's performance. A variety of thermal effects may take place on natural stones in historic buildings, and their investigation in laboratory simulations may be effective to support a reliable diagnosis of fire damage in order to select proper conservation measures. To this aim, this study reports on the high temperature effects on a highly porous calcareous stone. Analytical and microscopic techniques (X-Ray Diffractometry, Thermogravimetry and Differential Scanning Calorimetry, optical microscopy and SEM), were combined in a systematic investigation of chemical-mineralogical and microstructural modifications affecting the stone under increasing temperatures, up to 700 °C. Non-destructive ultrasonic velocity propagation (UPV) test and quantitative evaluations of colour changes and physical parameters relating to the stone microstructure were also performed. The overall findings highlight that thermal effects mainly compromised the aesthetic features of the investigated stone, through colour changes relating to chemical-mineralogical transitions. The damage to the stone microstructure due to thermal dilatations was limited, likely because of the high presence of pore spaces. Fissuring was observed microscopically, and also recorded through porosimetric changes and UPV decreases, but it led to negligible increases of both the open porosity and water uptake.

In this work, the effect of the Al content (x = 5, 10, and 15 at. %) on the martensitic transformation (MT) and microstructure and mechanical properties of CuZrAl alloys was studied. The microstructure of the alloys was characterized at room temperature by means of scanning electron microscopy and X-ray diffraction. An increase in Al content reduces the amount of transforming CuZr phase, and consequently the secondary phase formation is favored. The evolution of the MT upon thermal cycling was investigated as a function of the Al content by differential scanning calorimetry. MT temperatures and enthalpies were found to be decreased when increasing the Al content. Al addition can induce a sudden, stable MT below 0C, while the binary alloy requires ten complete thermal cycles to stabilize. Finally, the mechanical properties were investigated through microhardness and compression testing. No linear dependence was found with composition. Hardness lowering effect was observed for 5-10 at. % of Al content, while the hardness was increased only for 15 at. % Al addition with respect to the binary alloy. Similarly, compressive response of the alloys showed behavior dependent on the Al content. Up to 10 at. % Al addition, the alloys indicate a superelastic response at room temperature, while higher Al content induced untimely failure.

The present work explores the effect of a stress relieving heat treatment on the microstructure, tensile properties and residual stresses of the laser powder bed fused AlSi9Cu3 alloy. In fact, the rapid cooling rates together with subsequent heating/cooling cycles occurred during layer by layer additive manufacturing production make low temperature heat treatments desirable for promoting stress relaxation as well as limited grain growth: this combination can offer the opportunity of obtaining the best compromise between high strength, good elongation to failure and limited residual stresses. The microstructural features were analysed, revealing that the high cooling rate, induced by the process, caused a large supersaturation of the aluminum matrix and the refinement of the eutectic structure. Microhardness versus time curve, performed at 250C, allowed to identify a stabilization of the mechanical property at a duration of 25 h. The microstructure and the mechanical properties of the samples heat treated at 25 h and at 64 h, considered as a reference for the conventionally produced alloy, were compared with the ones of the as-built alloy. Finally, it was shown that a 59% reduction of the principal residual stresses could be achieved after the 25 h-long treatment and such evolution was correlated to the mechanical behaviour.

Among NiTi-based alloys, one of the most promising and exploited alloys is NiTiCu, since the addition of Cu in substitution of Ni in the binary equiatomic NiTi has a significant influence on the martensitic transformation and the thermomechanical properties of the system. A high content of Cu improves the damping properties at the expense of phase homogeneity and workability. The present study focuses on an alloy with a high copper content, i.e., 20 at.%. For this specific composition, the correlation between the thermal treatments, microstructure, formation of secondary phases, and damping properties are investigated by several analyses. The microscopic observation, together with the compositional analysis, allowed the determination of four different phases in the alloy. Both the calorimetry and dynamic thermo mechanical measurements, which confirmed the high damping ability of the alloy, provided a characterization of the martensitic transition. Finally, the electron backscatter diffraction (EBSD) analysis detected the different crystallographic structures (i.e., cubic austenite, orthorhombic martensite, and cubic (face-centered) NiTi2) and their orientation in the different phases. Therefore, the present work aims to improve the knowledge of the role of secondary phases in the optimization of the NiTiCu20 alloy as a valuable alternative to typical alloys used for damping purposes.

Among additive manufacturing (AM) processes, Selective Laser Melting (SLM) is the most diffused layer by layer method for manufacturing 3D components. It is based on local melting, induced by a laser scanning, on a powder bed; the limited dimensions of the liquid pool provoke rapid cooling rates which can be associated to significantly finer microstructure than the one obtained by a conventional casting process. Moreover, being the remelting of pre-existing pools, it is of relevant interest to investigate the wettability and the reactivity at high temperature of alloys produced by SLM. In the panorama of alloys for AM, the AlSiMg system is one of the most used, as it belongs to wide family of the Al-Si alloys, extensively used for conventional casting and die-casting technologies, and it offers good weldability. Therefore, the present work has the goal of investigating the high temperature behavior of the SLMed AlSiMg parts. Wettability tests on AlO plates were performed considering two different atmospheres (vacuum and Argon) and the contact angle results compared; surface morphology together with the microstructures and the chemical composition variations were analyzed.

The puzzling and challenging pre-Mesolithic human remains found at the al-Khiday site, Sudan, can not be dated directly by radiocarbon techniques or other means because of the extensive diagenetic processes that changed the microstructure of the bones and completely deprived the samples of organic matter. Here the micro- structural and micro-chemical investigations performed on these remains are reviewed. The results are combined with macroscopic evidence such as stratigraphic relationships, available radiocarbon dates of soil carbonates, and the regional palaeo-climatic frame in order to indirectly assign a Late Pleistocene age to this important group of humans. The al-Khiday case study is deemed to be an important and successful example of application of modern archaeometric techniques at the microscopic level.

Austempered Ductile Irons (ADIs) with different contents of nickel and copper were austenitized at the same conditions, and austempered for 60, 90 and 180 min to investigate the austempering evolution. Besides the conventional ductility analysis to assess the best austempering times, strain hardening analysis of tensile flow curves was carried out, since it has been found reliable for this assessment if dislocation-density-related constitutive equations are used. Through plotting the Voce equation parameters 1/? vs. ? found from the strain hardening analysis, Matrix Assessment Diagrams (MADs) were drawn, and austempering conditions closest to the best austempering times were identified. Austempering times found with ductility-criterion and MAD approach did not match. Mg-Cu particles found in copper-containing ADIs affected the reliability of tensile ductility that could not be ascribed to ausferrite stability only, while the austempering times found with MAD approach seemed to be consistent with solid-state diffusion transformations.