An acoustic technique operating at a frequency of about 100kHz and strain amplitudes of 10−7 to 2 x 10−4 was used to investigate diffusion mobility of point-like defects in the β1’ martensitic phase of a Cu–10.4Al–0.47wt%Be single crystal at temperatures down to 9K. Diffusion of the quenched-in point-like defects in the Cu–Al–Be martensite was detected by amplitude-dependent anelasticity at much lower temperatures than for other Cu-based martensitic alloys (Cu–Al, Cu–Al–Ni, Cu–Zn–Al). Strain amplitude dependence of the internal friction and Young's modulus defect indicated that the formation of pinning atmospheres at up to 200K was restricted to the regions swept up by oscillating partial dislocations/interfaces and, therefore, should be attributed to the efficient dislocation/interface-assisted diffusion of point-like defects. Observation of the intense defect-assisted diffusion in the Cu–Al–Be martensite accounted for the extremely strong “kinetic” stabilisation of martensite in Cu–Al–Be, which was evident from calorimetry data and was much less intense in other Cu-based martensites.

Defect-Assisted Diffusion and Kinetic Stabilisation in Cu–Al–Be β1’ Martensite. K.Sapozhnikov, S.Golyandin, S.Kustov, E.Cesari: Materials Science and Engineering A, 2008, 481-482, 532-7