Microstructural analyses of thermal or mechanical fatigued Nitinol show remarkable similarities and are characterized by an increase in dislocation density with increasing number of cycles. Dislocation bands, which are thought to be due to the effects of moving martensite interfaces, align with the martensite lattice invariant plane. These microstructural effects result in modification of trans...

Transformation induced plasticity (TRIP) assisted steels contain a small quantity of carbon enriched retained austenite, which transforms into martensite during the course of plastic deformation. Transformation of this kind can be induced by both stress and plastic strain. The detailed mechanism by which the martensite is induced is different for these two scenarios. An attempt is made here to ...

A Fe-34.5 wt % Mn-0.04 wt % C ultra-high Mn steel with a fully recrystallised fine-grained structure was produced by cold rolling and subsequent annealing. The steel exhibited excellent cryogenic temperature properties with enhanced work hardening rate, high tensile strength, and high uniform elongation. In order to capture the unique mechanical behaviour, a constitutive model within finite str...

Exchange bias effect observed in the Ni1.68Co0.32Mn1.20Ga0.80 alloy confirms the coexistence of antiferromagnetic and ferromagnetic phases in the martensite phase. A large inverse magnetocaloric effect has been observed within the martensitic transformation temperature range, which is originated from modified magnetic order through magnetic-field-induced phase transformation from partially anti...

This -paper corrects an error in a previous paper by Dechamps and Brown and presents a much improved model for the structure of -twins in Fe-Ni martensite. The model is based upon the dissociation of screw dislocations under the stress due to the martensitic transformation. Resume-Dans cet article, nouscorrigeons une erreurd'un article preced~nt de Dechamps et Brown et nous presentons un modele...

An overview will be given of some recent results of microstructural electron microscopy studies on martensitic systems. The precursor structure observed in a ternary Ni-Mn-Ti alloy and its correlation with the ensuing stacking sequence is presented. New types of materials of a well known alloy, in casu splat-cooled and nanoscale thin films of Ni-A1 are investigated revealing particular morpholo...

Realizing high work hardening and thus elevated strength–ductility synergy are prerequisites for the practical usage of body-centered-cubic entropy alloys (BCC-HEAs). In this study, we report a novel dynamic strengthening mechanism, martensitic twinning transformation mechanism in metastable refractory element-based BCC-HEA (TiZrHf)87Ta13 (at.%) that can profoundly enhance capability, leading t...

Controlling the morphology of nanocrystals (NCs) is of paramount importance for both fundamental studies and practical applications. The morphology of NCs is determined by the seed structure and the following facet growth. While means for directing facet formation in NC growth have been extensively studied, rational strategies for the production of NCs bearing structure defects in seeds have be...

Merohedral or pseudomerohedral twinning of crystals cannot be identified from inspection of the diffraction patterns. Several methods for the identification of twinning and the estimation of the twin fraction are suitable for macromolecular crystals and all are based on the statistical properties of the measured diffraction intensities. If the crystal twin fraction is estimated and is not too c...