A continuum thermodynamics formulation for micromagnetics coupled with mechanics is devised to model the evolution of magnetic domain and martensite twin structures in ferromagnetic shape memory alloys. The theory falls into the class of phase-field or diffuseinterface modeling approaches. In addition to the standard mechanical and magnetic balance laws, two sets of micro-forces and their assoc...

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...

An extra low carbon martensitic stainless steel with 16% ultrafine grained metastable reverted austenite was subjected to uniaxial tensile testing and investigated in-situ energy-dispersive synchrotron X-ray diffraction (XRD) electron backscatter (EBSD) reveal the complex interplay between stress, strain transformation. In-situ XRD demonstrated that, upon surpassing yield strength, fraction of ...

Lath martensite reveals a specific hierarchical subgrain structure, with laths, blocks and packets of particular crystallography. The presence of interlath retained austenite layers has been reported in the literature. This paper investigates the potential influence of the interlath retained austenite on the mechanical behaviour of lath martensite subgrains. To this purpose, a martensite grain ...

We study the behavior of crystals that undergo martensitic transformations. On cooling, the high-temperature phase (austenite) transforms to the martensite phase changing its crystalline symmetry. The lower crystalline symmetry of the martensite gives rise to several variants of martensite. Each variant has an associated transformation strain. These variants accommodate themselves (according to...

Shape-memory hacks were fabricated in a single processing step ("one-time procedure") by a combination of tensile and bending deformation of a martensitic NiTi-wire. The hacks reversibly changed curvature on heating and cooling in a reproducible manner over 50 thermal cycles. This new type of intrinsic two-way shape memory effect was studied by subjecting the hacks to a beam of high-energy sync...

The effect of cold swaging and subsequent annealing on the structure mechanical properties a 321-type metastable austenitic stainless steel was studied. Cold to strain 90% produced gradient with gradual decrease in α-phase content from edge center bar. Globular lamellar regions both strain-induced martensite retained austenite were found center, meanwhile, completely globular austenite–martensi...

Quenching & Partitioning (Q&P) steels owe their good strength-ductility combinations to the martensite/austenite (α’/γ) mechanical interactions and formation of mechanically-induced martensite (α′mech) through transformation-induced plasticity (TRIP) effect. An essential role is played by carbon, whose distribution among phases can be modified Q&P route. This study presents a methodology system...

Micro-shot peening on AISI 304 and 316 stainless steel (SS) laser welds was performed to evaluate its effect the susceptibility stress corrosion cracking (SCC) in a salt spray containing 10% NaCl at 80 °C. The of disclosed by testing U-bend specimens spray. caused an intense but narrow deformed layer with nanocrystal structure residual compressive stress. Austenite martensite transformation occ...