摘要
HfV 2, like most Laves phase alloys, is brittle at low temperatures, but when it is alloyed with Nb, substantial deformation is possible—by twinning. These twins are the standard fcc type twins, lying on (111) planes with shears in the 〈112〉 direction. HREM of the twins shows that they have the same macroscopic shear as twins in fcc crystals, which means that the twinning must be accompanied by atomic shuffles or synchroshear in order to preserve the ordered structure. Given the nature of the material, it was concluded that the mechanism is synchroshear. The HfV 2+Nb alloys have been deformed over a wide temperature range, from 4 K to 1 300 K. An anomaly in the temperature dependence of the flow stress was observed at about 77 K, where there is a precipitous dip in the flow stress. The dip at 77 K has been attributed to an increased ease of twinning (which is taken to be strong evidence against atomic shuffles).
HfV 2, like most Laves phase alloys, is brittle at low temperatures, but when it is alloyed with Nb, substantial deformation is possible—by twinning. These twins are the standard fcc type twins, lying on (111) planes with shears in the 〈112〉 direction. HREM of the twins shows that they have the same macroscopic shear as twins in fcc crystals, which means that the twinning must be accompanied by atomic shuffles or synchroshear in order to preserve the ordered structure. Given the nature of the material, it was concluded that the mechanism is synchroshear. The HfV 2+Nb alloys have been deformed over a wide temperature range, from 4 K to 1 300 K. An anomaly in the temperature dependence of the flow stress was observed at about 77 K, where there is a precipitous dip in the flow stress. The dip at 77 K has been attributed to an increased ease of twinning (which is taken to be strong evidence against atomic shuffles).
出处
《中国有色金属学会会刊：英文版》
CSCD
1999年第S1期169-179,共11页
Transactions of Nonferrous Metals Society of China
