Zr基块体非晶合金玻璃形成能力与压铸成型性能研究

The glass-forming ability and die casting performance of Zr-based bulk metallic glasses

本文分析了熔体温度、铸造压力和化学成分对非晶合金玻璃形成能力(GFA)与压铸成型性能的影响,并探究两种性能的工艺关联。研究发现:随熔体温度升高,Zr基非晶合金GFA先提高后减小,且合金成分不同,熔体化学成分,局域原子团簇特征和合金实际冷却速率就不同,非晶合金GFA与玻璃稳定性也就存在差异。非晶合金的压铸成型能力随熔体温度和铸造压力升高不断提高,但与GFA存在相互限制的作用:当合金GFA较强时,熔体内原子堆垛密实,粘滞系数较高严重阻碍过冷液流动成形,且玻璃稳定性越好压铸成型性能越差;而当熔体温度过高,非晶合金GFA减弱,过冷液粘度降低时,才能快速提高非晶合金的压铸成型性能。因此,选择最佳的合金成分、优化工艺参数有利于非晶精密结构件成型。

In this study,the effects of the melt temperature,casting pressure and chemical composition on the glass-forming ability(GFA)and die casting performance of metallic glasses were investigated,and the relationship between those two properties were further explored.It was found that the GFA of Zr-based metallic glasses initially slightly increased and then decreased with increasing melt temperature.Moreover,the GFA and stability of metallic glasses vary considerably due to chemical inhomogeneity,local atomic clusters,as well as actual cooling rate.The casting performance of metallic glasses improved with increasing of melt temperature and casting pressure,but showing mutual restriction with the GFA.Once the alloy has a strong GFA,the dense atomic clusters and larger viscosity coefficient can dramatically hinder the flow forming of the supercooled liquids,especially for the alloys with high thermal stability.However,the overheating of the melt would cause weak GFA and decreased viscosity,and so enhance die casting performance.Therefore,choosing appropriate compositions and optimizing casting parameters facilitate precision forming of structural parts.