Zr_(55)Al_(10)Ni_5Cu_(30)大块非晶合金的超塑性挤压成形性能

Superplastic extrusion behaviors of Zr_(55)Al_(10)Ni_5Cu_(30) bulk metallic glass

通过示差扫描量热分析确定了Zr55Al10Ni5Cu30大块非晶合金的过冷温度区域范围, 采用应变速率突变压缩实验分析了合金在450℃时的力学性能, 研究了合金在不同挤压速度、不同真空度等工艺条件下的挤压成形性能。结果表明: Zr55Al10Ni5Cu30大块非晶合金的玻璃化转变开始温度Tg 为422.4℃, 晶化开始温度Tx 为482.4℃; 在450℃、应变速率小于5×10-3 s-1的条件下, 合金的流动应力小于 40 MPa; 在挤压速度为 0.002~0.004mm/s范围内挤压时, 合金的最大挤压载荷变化较小; 在挤压温度为450℃时, 合金的最大挤压力随着真空度(2~2×10-3 Pa)的提高而增加; 大块非晶合金在超塑性成形时呈现出比一般金属材料更大的摩擦阻力。

Super-cooled liquid region was determined through differential scanning calorimetric, and mechanical properties were analysed by strain rate increase test for Zr_(55)Al_(10)Ni_5Cu_(30) at 450℃. The superplastic extrusion experiments were carried out under different extrusion velocities and vacuum degrees. The results show that the glass transition temperature T_g of Zr_(55)Al_(10)Ni_5Cu_(30) is 422.4℃, and the crystallization temperature T_x is 482.4℃. At the temperature of 450℃ and strain rate less than 5×10^(-3)s^(-1), the flow stress of the alloy is less than 40MPa. When extrusion velocities varying from 0.002mm/s to 0.004mm/s, the differences of maximal extrusion loads are not obvious. At 450℃, the maximal extrusion load increases with the rising vacuum degrees (22×10^(-3)Pa). In superplastic forming, bulk metallic glass has larger surface friction resistance than ordinary metal alloys.