Evaluation of the Shape Memory Effect by Micro-Compression Testing of Single Crystalline Ti-27Nb Ni-Free Alloy

Abstract

In this work, micro-compression tests are performed at various temperatures with Ti-27Nb (at.%) single crystalline pillars to investigate anisotropic deformation behavior, including the shape memory effect. In non-tapered single-crystal pillars with loading directions parallel to [001], [011], and [111], transformation strain and stress show orientation dependence. [001]-oriented micropillars with aspect ratios of 2 and 1.5 demonstrate temperature-dependent transformation stress during micro-compression at various temperatures. Although more stress is required to induce martensite transformation in the pillar with the lower aspect ratio, the temperature dependence of ~1.8 MPa/K observed in both pillars is in good agreement with that of bulk Ti-27Nb.

Special Issue: Ti-Based Biomaterials: Synthesis, Properties and Applications

“…The main problem related with most commonly used Nitinols as shape memory alloys in medical industry is Ni as carcinogen. Nagoshi et al [9] shows shape memory Ni-free β-type Ti-Nb alloys. The mechanical behavior of single crystalline micropillars was investigated in the microscale at various temperatures and crystal orientations to shows anisotropic deformation behavior and shape memory effect.…”