Shape memory alloys exhibit a high damping capacity in the mktensite state. Results obtained from both DMA and cyclic tests under tension-compression load show that the martensite damping capacity in NiTi SMAs is a function of both strain amplitude and annealing temperature. Internal friction due to movements of martensite twin boundaries within both elastic (accommodation) and inelastic (reori...

The name martensite is after the German scientist Martens. It was used originally to describe the hard microconstituent found in quenched steels. Martensite remains of the greatest technological importance in steels where it can confer an outstanding combination of strength (> 3500MPa) and toughness (> 200MPam 1 2 ). Many materials other than steel are now known to exhibit the same type of soli...

This conference paper briefly discusses different techniques for measuring the evolution of the martensite content in cold-rolled stainless steel 301LN sheets under mechanical loading. Three methods are employed to measure the martensite content: (1) micrography, (2) bulk magnetic induction, and (3) local magnetic permeability measurements. The first two methods require the extraction of sample...

Modulated phases occur in numerous functional materials like giant ferroelectrics and magnetic shape-memory alloys. To understand the origin of these phases, we employ and generalize the concept of adaptive martensite. As a starting point, we investigate the coexistence of austenite, adaptive 14M phase, and tetragonal martensite in Ni-Mn-Ga magnetic shape-memory alloy epitaxial films. We show t...

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.

Metastable austenitic steels react to plastic deformation with a thermally and/or mechanically induced martensitic phase transformation. The transformation ?’-martensite can take place directly or indirectly via the intermediate stage of ?-martensite from single-phase austenite. This effect is influenced by stacking fault energy (SFE) steels. An SFE < 20 mJ/m2 known promote indirect conversi...

This paper aims at the phase identification and quantification in transformation induced plasticity duplex stainless steel (TDSS) base weld metal containing ferrite, austenite, martensite. Light optical microscopy (LOM) electron backscatter diffraction (EBSD) analysis were employed to analyze phases. Samples either mechanically or electrolytically polished study effect of preparation technique....

The hydrogen embrittlement (HE) behavior of a commercial QP980 steel is studied in this work. HE susceptibility results indicate that suffers from severe HE, and the fracture mode transforms ductile dimpling to brittle quasi-cleavage under attack hydrogen. EBSD show strain-induced martensite transformation can rarely occur at strain close strain, which mainly attributed high mechanical stabilit...

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 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...