Utilizing electrical resistance measurements in combination with strain observations on single crystals, it was possible to distinguish the austenite to martensite transformation from the detwinning of the martensite behavior during deformation of NiTiCu shape memory alloys. It was found that the electrical resistance change associated with the detwinning of the martensite variants was as high ...

Stress-induced martensitic transformations are clarified in classes of NiMnGa alloys which undergo the stress-free, thermal-induced inter-martensite transformation austenite (A) pre-martensite (PM) martensite. This study implements a comprehensive experimental approach, including analysis of the strain–temperature and stress–strain response, which discloses stress-induced inter-martensite trans...

Abstract Although martensitic transformation is neither necessary nor sufficient to explain hydrogen effects in austenitic stainless steels, the formation of a second phase upon straining results local strain incompatibilities within microstructure which can result assisted crack initiation. The fraction α’-martensite on fracture surfaces ten commercial steels different austenite stability was ...

Quenching and Partitioning (Q&P) steels are, due to their excellent combination of strength ductility, seen as good candidates for the third generation advanced high (AHSS). Although TRIP effect is beneficial overall mechanical behaviour these it potentially can have detrimental effects when strained in a hydrogenenriched environment. The solubility hydrogen austenite but low carbon martens...

We have demonstrated the utility of nanoindentation as a rapid characterization tool for mapping shape memory alloy compositions in combinatorial thin-film libraries. Nanoindentation was performed on Ni–Mn–Al ternary composition spreads. The indentation hardness and the reduced elastic modulus were mapped across a large fraction of the ternary phase diagram. The large shape memory alloy composi...

The non-linear nature of the superelastic phase transformation in NiTi means that conventional fatigue life theory is difficult to apply. The volume fraction of martensite/parent phase and its role in the fatigue mechanism is not understood. This paper considers the fatigue life of superelastic NiTi alloys when tested at 2Hz in Ringers solution. In agreement with other researchers [1] [2] it wa...

Abstract In this study, dual-phase (DP, ferrite + martensite) microstructures were obtained by performing intercritical heat treatments (IHT) at 750 and 800 °C followed quenching. Decreasing the IHT temperature from to leads to: (i) a decrease in volume fraction of austenite (martensite after quenching) 0.68 0.36; (ii) ~ 100 martensite start (Ms), mainly due higher carbon content its smaller gr...

A quantitative and automated phase analysis of dual-phase (DP) steel using electron backscatter diffraction (EBSD) was attempted. A ferrite-martensite DP microstructure was produced by intercritical annealing and quenching. An EBSD map of the microstructure was obtained and post-processed for phase discrimination. Band slope (BS), which was a measure of pattern quality, exhibited much stronger ...

The possibility to obtain multiphase steels with considerable fractions of retained austenite, which is of key interest for the occurrence of the TRIP effect, is investigated in steels with low amounts of Si and Al. Special emphasis is dedicated to the microstructural observation of this phase, since its volume fraction, distribution and stability, related to the carbon content, will determine ...

in this study, the effects cold rolling and annealing parameters during thermomechanical processing of the aisi 201ln stainless steel were investigated. the cast samples were homogenized, hot-rolled and solution-annealed to acquire a suitable microstructure for the subsequent thermomechanical treatment. unidirectional and transverse multi-pass cold rolling at 25, 0 and -15 °c was carried out to...