Mechanical properties of nanocrystalline L1_2-type (Al + 12.5 at. M)_3Zr (M=Cu, Mn) synthesized by mechanical alloying

摘要

Nanocrystalline L1_2-type (Al + 12.5 at.% M)_3Zr (M=Cu, Mn) alloys with grain sizes of 8 to 10 nm were prepared by MA and SPS. The micro-hardness was measured to be as high as 975.8 Hv and 983.9 Hv for Cu- and Mn- added alloys, respectively. However, their fracture toughness was below 2 MPam~(1/2). The result may indicate that a grain refinement towards the nano scale dose not have a beneficial effect on improving fracture toughness in brittle intermetallics. In this study, some attempts have been made to investigate the effects of grain size on the fracture toughness and the results are presented and discussed.