Stress induced martensite transformation in Co-28Cr-6Mo alloy during room temperature deformation

The phase transformation and texture change of two Co-28Cr-6Mo alloys during room temperature deformation were studied by using the in-situ synchrotron X-ray diffraction. It is found that a slight difference in chemical compositions can significantly change the phase constitutions and the mechanical properties. For the material with less Ni, C and N (lower α-phase stability), increasing the grain size promotes the athermal martensite transformation during cooling. The kinetics of the Stress Induced Martensite (SIM) phase transformation may be more affected by the athermal martensite instead of the grain size of the α-phase. After deformation, similar textures are produced in samples regardless the differences in the initial structures such as the phase constitution and the grain size; while a relatively strong {111} texture and a weak {100} texture are produced in the α-phase, a {101¯1} fiber texture is gradually developed in the ε-phase during uniaxial tension.