轧制塑性变形对Zr60Al15Ni25非晶合金的自由体积及力学性能影响

Influence of Rolling Plastic Deformation on Free Volume and Mechanical Property of Zr60Al15Ni25 Amorphous Alloy

摘要:

利用差示扫描量热法（DSC）研究了室温轧制塑性变形对Zr60Al15Ni25非晶合金自由体积及力学性能的影响。结果发现，随着轧制变形量ε的增加，合金的显微硬度呈下降趋势，从铸态到ε=95%，硬度下降最大幅度约10%。DSC曲线上玻璃化转变之前的弛豫热随变形量的增大而提高，表明非晶合金在塑性变形后自由体积增多。非晶合金力学性能的下降可能是由于剪切带内过剩的自由体积在塑性变形终止后聚集为纳米空洞，空洞的存在造成合金粘度的降低。

Abstract:

Variation of the free volume of Zr60Al15Ni25 amorphous alloy during rolling plastic deformation and its influence on the mechanical property were investigated by differential scanning calorimetry (DSC). Results show that the Vickers microhardness decreases with increment of deformation degree ε, and the maximum reduction reaches about 10% from as-cast state to ε=95%. However, in the DSC curves the released energy due to relaxation before glassy transformation increases with ε increasing. It is concluded that the free volume in the amorphous alloy increases after plastic deformation. The excess free volume in shear zone maybe coalesces into nano-sized voids as deformation ceases. The existence of those voids leads to the decrease of the viscosity, i.e., the decline of the Vickers hardness.