铸、锻两种状态下TiNiNb合金的热加工性能

Hot Workability for As-Cast and As-Forged TiNiNb Alloys

由热模拟压缩实验数据分别建立铸态和锻态2种组织状态的TiNiNb合金的本构方程,并采用多项式构建Arrhenius双曲正弦型本构方程参数A、n、α、Q与ε的函数关系。从热变形激活能随不同影响因子的变化规律出发,探究该合金在不同组织状态下的热加工性能。结果表明:铸态TiNiNb合金的流变应力略高于锻态,这主要与金属间化合物的长程有序点阵结构有关,铸态合金的适宜加工参数范围为应变速率ε小于0.1s-1,最大应变小于0.4,锻态合金的适宜加工参数范围为应变速率ε小于0.56s-1,最大应变小于0.5。

The deformation behavior of as-cast and as-forged TiNiNb alloy was studied at elevated temperature by compressive deformation tests from Gleeble-1500D Thermal Simulator.Based on the analyses,constitutive equations which related the flow stress to temperature,strain rate and strain have been respectively established.Results indicate that the flow stresses of as-cast TiNiNb alloy are slightly higher than that of as-forged alloy under the same condition.The optimum parameter ranges for processing of as-cast TiNiNb alloy are below 0.1 s-1 for strain rate and below 0.4 for strain,while the optimum parameter ranges for processing of as-forged TiNiNb alloy are below 0.56 s-1 for strain rate and below 0.5 for strain.