应变速率对Zr_(67.76)Cu_(11.94)Ni_(8.30)Al_(12)非晶复合材料力学性能及锯齿流变行为的影响

Effects of Strain Rates on Mechanical Properties and Serrated Flow Behaviors of Zr_(67.76)Cu_(11.94)Ni_(8.30)Al_(12) Metallic Glass Composite

采用统计学方法研究了应变速率对Zr_(67.76)Cu_(11.94)Ni_(8.30)Al_(12)非晶复合材料力学性能及锯齿流变行为的影响。结果表明:随着应变速率的增加,材料的塑性应变减小,抗压强度下降;同时应力降幅Δσ的锯齿分布从单调下降分布转变为峰状分布,应力降幅的频数由小应力降幅区间向大应力降幅区间过渡,单位塑性应变的锯齿频数M呈下降趋势,试棒侧面剪切带数量减少且相互交割、分支、阻止作用明显减弱,此时,由多重剪切带扩展转变为单一剪切带扩展,使得材料的力学性能迅速下降。

The influences of strain rates on mechanical properties and serrated flow behaviors of Zr67.76Cu11.94Ni8.30Al12 metallic glass composite have been investigated with statistical methods. The results demonstrate that both the plastic strain and the compressive strength decrease with the increasing of strain rates. Meanwhile, the serrated distribution of stress drop（Δσ） changes from monotonically decreasing into a peak-like shape, and the absolute frequency transits from a small interval to a large one. The serrated number of unit plastic strain（M） continuously declines. Moreover, the number of the shear bands decreases and the interaction among them significantly weakens. In the meantime, the extension transforms from multiple shear bands to a single shear band, resulting in the rapid decline in mechanical properties of the composite.