The experimental facts on the stabilisation of martensite in copper base shape memory alloys, of interest to the scientific investigator and the practical alloy processor and user are reported. Factors that have an influence on stabilisation are considered in this respect. The mechanisms proposed in the literature to explain stabilisation are critically examined.

AISI 301 stainless steel is a frequently used metal, especially in high temperature demands and or in part with high corrosion risk. Thin spring steel plates can be used as expansions of heat furnaces insulation and variety of all other springs. The present study has assessed the effects of temperature and thermal treatment time span on the microstructure of stainless steel 301 to achieve elast...

Plastic deformations, such as those obtained by shot peening on specimen surface, are an efficient way to improve the mechanical behavior of metals. Generally, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) are commonly used to observe the complex microstructural evolutions, such as grain refinement and phase transformation, induced by the surface treatment. In...

spear-like martensite thermally formed in the same alloy in several respects such as in shape, lattice invariant shear, habit plane and orientation relationship, even though both have the same crystal structure and lattice parameters. The lattice invariant strain of the martensite was found to be stacking faults on the basal plane, and a defectless region was observed at the middle of the marte...

The fct martensite morphology and the martensite transformation temperatures are examined for Pd-rich Fe–Pd–Pt alloys, which have the composition of Fe–(xPdyPt)xþy1⁄430 at:%. The replacement of Pd with Pt content causes solution hardening. The shape memory effects are investigated below the Af temperatures. Above the Af temperatures, the stress induced martensite in several grains completely di...

This paper provides an overview on obtaining low-carbon ultra-fine grained dual-phase steels through rapid intercritical annealing of cold-rolled sheet as improved materials for automotive applications. A laboratory processing route was designed that involves cold-rolling of a tempered martensite structure followed by a second tempering step to produce a fine grained aggregate of ferrite and ca...

The two-way shape memory effect in a Ti36Ni49Hf15 high temperature shape memory alloy (SMA) has been systematically studied by bending tests. In the TiNiHf alloy, the martensite deformation is an effective method to get two-way shape memory effect even with a small deformation strain. When the TiNiHf alloy is deformed at a full martensite state, the deformation mechanism is the martensite orien...

Pseudoelasticity and the shape memory e ect (SME) due to martensitic transformation and reorientation of polycrystalline shape memory alloy (SMA) materials are modelled using a free energy function and a dissipation potential. Three di erent cases are considered, based on the number of internal state variables in the free energy: (1) Austenite plus a variable number of martensite variants; (2) ...

Ni-Mn-Ga is a ferromagnetic shape memory alloy that deforms by twin boundary motion. The magneto-mechanical properties depend strongly on the twin microstructure. A thermomechanical treatment was applied to a Ni-Mn-Ga single crystal with coexisting 10M and 14M martensite structures to create twin boundaries and align the short crystallographic c direction preferentially perpendicular to the sur...