In situ AFM observation of crack propagation in CuNiAl shape memory alloy

The nucleation and propagation behaviors of cracks in CuNiAl shape memory alloy were observed using in situ technique under atom force microscope (AFM). The results indicated that, in CuNiAl shape memory alloy, the martensitic transformation first occurred at crack tip upon loading, and then the microcrack nucleated and propagated along martensite interface. The slip bands appeared only after considerable crack propagation. After that, the crack usually propagated alternately along martensite interface or slip bands.