Zr基与Ti基非晶合金的不同划痕变形行为

采用痕法研究了Zr47.9Ti0.3Ni3.1Cu39.3Al9.4与Ti40Zr25Be30Cr5两种非晶合金的塑性变特征,考查了载荷与痕速度对塑性变特征的影响.结果表明两种铸态非晶合金样品的剪切带表现出同的特征：Ti非晶合金在痕两侧剪切带现分枝特征,随着载荷和痕速度的增加,出现多重分枝和混乱分特征;而Zr非晶合金的剪切带特征以一次剪切带为主,随载荷和痕速度增加,剪切带特征向单一、平滑趋势转变.进一研究了弛豫对Zr非晶合金痕变特征的影响,发现弛豫使Zr非晶合金剪切带向分枝特征转变.从自由体积观点探讨了两种合金中同剪切带特征的和演制.

Deformation patterns in Zr-based and Ti-based metallic glasses under scratch processes

The plastic deformation features of Zr-and Ti-based bulk metallic glasses（BMGs） are investigated by scratch method under different applied load and scratch velocity.The results show that the two BMG systems exhibit quite different shear band features during scratch processes.Shear band branching are found in Ti-based BMG,and the branching are more prominent at high applied load and rate during the scratch process.In contrast,the Zr-based BMG shows primary shear band dominating pattern,which becomes more straight and regular at high load and rate.Furthermore,the effect of structural relaxation on the shear band feature during scratch tests is studied.It is found that relaxation gives rise to a distinct transition from primary shear band dominating pattern to a branching and irregular pattern in the Zr-based BMG.The mechanism of change of the shear band pattern is discussed in the view of free volume theory.