We provide an extended Peierls–Nabarro (P–N) formulation with a sinusoidal series representation of generalized stacking fault energy (GSFE) to establish flow stress in a Ni2FeGa shape memory alloy. The resultant martensite structure in Ni2FeGa is L10 tetragonal. The atomistic simulations allowed determination of the GSFE landscapes for the (111) slip plane and 2 1⁄2 101 ; 2 1⁄2 110 ; 6 1⁄2 211...

The hysteresis loop, described during the formation of stressinduced pseudoelastic martensite in a Cu-Zn-A1 betaphase single crystal, was studied as a function of strain-rate, deformation amplitude and temperature. The aPtm, the stress at which the transformation starts at a given constant temperature, is strain-rate independent but the hysteresis described by the stress-strain curve shows a ma...

For Fe-Mn-Si-Cr-Ni shape memory alloys, it was previously found by HREM study that the formation of the nanometric lamella structures consisting of f.c.c. and h.c.p. phase is very important to exhibit good shape memory effect. In the present work, the formation process of such lamella structures has been studied in detail. The results are as follows. The transformation is initiated by random fo...

in this study, the effects of nitrogen addition on the production of ultrafine/nano grained aisi 201l stainlesssteel by advanced thermo-mechanical process were investigated. cast samples were first homogenized at 1200 °c for 4 h, hot-rolled at 1100 °c and finally, solution-annealed at 1150 °c for 2.5 h. unidirectional and cross multipass cold rolling at 25 °c was carried out to 90% reduction in...

Strain-induced phase transformation and damage accumulation in austenitic stainless steel subjected to cyclic loading were investigated by nondestructive evaluation. The cyclic loading test was performed at various strain amplitudes at the same strain rate. The volume fraction of the strain-induced phase transformation (α′-martensite) was determined by ferrite scope and magnetic coercivity meas...

this study was conducted in order to investigate the influence of plastic deformation on the transformation of retained austenite in a trip steel with a high content of al and a low content of si. to the aim, appropriate treatments were used to produce the starting material (trip steel). the microstructure of the obtained steel was composed of bainite and phases including ferrite and retained a...

Cu-Al-Ni single crystals with composition 82.6Cu-13.4A1-4Ni (wt%) were heat treated at 800°C for 30 rnin and subsequently water quenched to room temperature. The samples with 3 mm diameter and length between 100 and 200 mm had a longitudinal orientation close to the [001] direction of the P-phase at high temperature. The martensite start temperature after the initial heat treatment was MS=93"C....

The austenite-to-martensite transformation in a partially hardened stainless steel containing 17wt %Cr, 7wt %Ni and 1wt % Al was investigated with Vibrating Sample Magnetometry and Electron Back-Scatter Diffraction. Magnetometry demonstrated that measurable martensite formation can be suppressed on fast cooling to 77K as well as on subsequent fast heating to 373 K. Surprisingly, martensite form...

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...

Martensitic transformation plays a pivotal role in the microstructural evolution and plasticity of many engineering materials. However, so far the underlying atomic processes that accomplish the displacive transformation have been obscured by the difficulty in directly observing key microstructural signatures on atomic scale. To resolve this long-standing problem, here we examine an AISI 304 au...