The structure and nanoscale mechanical properties of Ni48.8Mn27.2Ga24 thin film fabricated by DC magnetron sputtering are investigated systematically. The thin film has the austenite state at room temperature with the L21 Hesuler structure. During nanoindentation, stress-induced martensitic transformation occurs on the nanoscale for the film annealed at 823 K for 1 hour and the shape recovery r...

Martensitic transfromation in TiNi alloys of the near-equiatomic composition has been studied by utilizing electron microscopy and diffraction under various thermal treatments. It has been observed that the martensitic transformation is associated with the variants of the product. Two orientations of the martensitic phase were observed as adjacent regions in quenched alloys. These orientations ...

Titanium-based shape memory alloys undergo a cubic to orthorhombic martensitic transformation (β to α’’ martensite). A new easy way operating as a reconstruction of the parent microstructure is used from electron backscattered diffraction. It is shown that the electron backscattered patterns of the martensitic microstructure can be directly indexed as the parent phase in order to obtain the cor...

Metastable ω phase is common in body-centred cubic (bcc) metals and alloys, including high-alloying steels. Recent theoretical calculations also suggest that the ω structure may act as an intermediate phase for face-centred cubic (fcc)-to-bcc transformation. Thus far, the role of the ω phase played in fcc-bcc martensitic transformation in carbon steels has not been reported. In previous investi...

This paper is aimed at studying the effect of a magnetic field on the martensitic transition of a Cu–Al–Mn shape-memory alloy. The martensitic transition has been studied through resistance measurements under applied magnetic fields ranging from 0 to 50 kOe. Negative magnetoresistance showing an almost linear dependence with the square of the magnetization has been observed. This magnetoresisti...

We present a numerical method for the approximation of microstructure in martensitic crystals by piecewise laminates, and we give computational results for several three-dimensional models of martensitic microstructure by using piecewise second-order laminates.

A workshop has explored interactions of materials science, applied mechanics, physics and mathematics in understanding fundamentals of martensitic transformations. System theory offers a framework for addressing realistic complexity. Theory of invariant-plane kinematics has been extended to multivariant plate groups and hierarchical structures. Electronic total energy calculations explore the o...

dissimilar metals friction welding of austenitic–martensitic stainless steels is commonly used in order to manufacture engine valves in the automobile industry. in this study, x53crmnnin219 (austenitic stainless steel) and x45crsi93 (martensitic stainless steel) valve steel rods were welded by friction welding process. the welded joint was then heat treated at 760 0c for 60 min. mechanical prop...

We predict the existence of a new ferromagnetic shape memory alloy Ga2MnNi using density functional theory. The martensitic start temperature (TM ) is found to be approximately proportional to the stabilization energy of the martensitic phase (δEtot) for different shape memory alloys. Experimental studies performed to verify the theoretical results show that Ga2MnNi is ferromagnetic at room tem...

The influence of Cu substitution for Mn on magnetic properties and magnetic entropy change has been investigated in Heusler alloys, Ni50Mn35−xCuxSn15 (x = 2,5 and 10). With increasing Cu content from x = 2 to x = 5, the martensitic transition temperature, TM , decreases from 220 K to 120 K. Further increasing Cu up to x = 10 results in the disappearance of TM . For samples Ni50Mn33Cu2Sn15 and N...