Zr基大块非晶合金的超塑性成形性能

Superplastic forming properties of Zr-based bulk amorphous alloys

研究了Zr41.25Ti13.75Ni10Cu12.5Be22.5大块非晶合金的过冷温度区域范围、时间—温度—转变曲线及其在过冷温度区域的力学行为,并在此基础上,对精密凸轮零件进行了模锻成形实验,分析了不同温度和应变速率对成形结果的影响。结果表明:Zr41.25Ti13.75Ni10Cu12.5Be22.5大块非晶合金在635.6～710.4K的过冷区域范围内,其应变速率敏感系数接近1,具有良好的超塑性性能;较理想的超塑性成形温度为653～668K,应变速率为5.0×10-4～5.0×10-3s-1。在温度为668K、应变速率为5.0×10-4s-1的工艺条件下,非晶合金的可成形时间大于1000s,最大流动应力小于70MPa。

Super-cooled liquid region, time-temperature-transformation diagram, and mechanical behavior of (Zr_(41.25)Ti_(13.75))Ni_(10)Cu_(12.5)Be_(22.5) in the super-cooled liquid region were investigated , and based on which , precision cams are fabricated by using die forging method. The effects of different temperatures and different strain rates on the formability were analyzed. The results show that Zr_(41.25)Ti_(13.75)Ni_(10)Cu_(12.5)Be_(22.5) bulk amorphous alloy exhibits a good superplasticity formability in the super-cooled liquid region of 635.6710.4 K with the strain rate sensitivity exponent m-(value) being approximately 1.0. The acceptable temperature and strain rate range for superplastic forming of this material are 653 668 K and 5.0×10^(-4) 5.0×10^(-3) s^(-1) respectively. Under the processing conditions of 668 K and 5.0×10^(-4) s^(-1), the incubation time for retaining the glassy phase without decomposition reaches 1 000 s and the largest flow stress is less than 70 MPa.