研究了Zr41.25Ti13.75Ni10Cu12.5Be22.5 (原子分数, %)块体非晶合金在玻璃转变终了温度Tg end附近的4个 特征温度点(616, 636, 656和676 K)的等温拉伸行为. 结果表明, 块体非晶合金的超塑性能与环境温度及拉伸速 度紧密相关. 在656 K, 以5 mm/min的速度 拉伸时, 获得了1625%的最大延伸率. 利用速度突变法测出了 636, 656及676 K时的应力敏感指数分别为0.25, 0.65和0.93. 利用自由体积模型对块体非晶合金的超塑性 流变行为的微观机制进行了分析.
Isothermal tensile tests of Zr41.25Ti13.75Ni10Cu12.5Be22.5 bulk metallic glass in supercooled liquid region are carried out at four characteristic temperatures of 616 , 636, 656 and 676 K which are in the vicinity of the end temperature of glass transition. Experimental results indicate that the superplastic flow behaviors of the material, viz., the flow stress and the elongation depend strongly on the testing temperature and tensile rate. The elongation increases firstly and then decreases with increasing rate and the maximum elongation reaches 1625% at 656 K and 5 mm/min. The strain rate sensitivity exponents determined by using Backofen method are 0.25, 0.65 and 0.93 at 636 , 656 and 676 K, respectively. The free volume model is used to interpret the observed superplastic flow behavior.
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