热压烧结Zr-6Al-0.1B合金Johnson-Cook本构模型的建立与精度分析

Establishment and Precision Analysis of Johnson-Cook Constitutive Model for Hot Pressing Sintered Zr-6Al-0.1B Alloy

锆铝合金是一种潜在的航天空间材料,采用真空热压烧结制备了Zr-6Al-0.1B合金,采用Gleeble-3500热模拟试验机对热压烧结Zr-6Al-0.1B合金在变形温度950~1150℃、应变速率0.01~1 s^(-1)条件下进行等温压缩试验。结果表明,在变形初期,应力随应变增加急速升高,迅速达到峰值。而后,随着应变的增加应力持续减小,而不存在应力平衡阶段。随着变形温度的降低或应变速率的增加,应力-应变曲线整体向高应力区域偏移,表明热压烧结Zr-6Al-0.1B合金属于变形温度和应变速率敏感材料。构建了热压烧结Zr-6Al-0.1B合金的Johnson-Cook本构模型,对温度敏感系数D和应变速率敏感系数C进行了修正。通过模型预测值与试验值的定性和定量对比分析表明,单独修正系数C时,模型具有较高的预测精度。本研究可为热压烧结Zr-6Al-0.1B合金后续热加工工艺参数的选择提供指导,并为相应的数值模拟研究提供可靠的本构模型。

ZrAl alloy is a potential space material for aerospace.Zr-6Al-0.1B alloy was prepared by vacuum hot pressing sintering.The isothermal compression tests of hot-pressed sintered Zr-6Al-0.1B alloy were conducted under the deformation temperature of 950-1150℃and the strain of rate of 0.01-1 s^(-1) by Gleeble-3500 thermal simulation machine.The results show that at the beginning of deformation,the stress is increased rapidly with increasing the strain and it reaches the peak stress quickly.Then,the stress is decreased continuously with increasing the strain,and there is no stress equilibrium stage.With decreasing the deformation temperature or increasing the strain rate,the stress-strain curve shifts to the high stress region,indicating that the hot-pressed sintered Zr-6Al-0.1B alloy is sensitive to deformation temperature and strain rate.The Johnson-Cook constitutive model of hot-pressed sintered Zr-6Al-0.1B alloy was established,and the temperature sensitivity coefficient D and strain rate sensitivity coefficient C were modified.Through the qualitatively and quantitatively comparative analyse between the predicted value by the model and the tested value,the model shows better prediction accuracy when C is modified alone.This study provides guidance for the selection of subsequent hot working parameters of hot-pressed sintered Zr-6Al-0.1B alloy,and provides a reliable constitutive model for the corresponding numerical simulation research.