摘要
针对新研制的高Nb-TiAl合金(Ti-45Al-8Nb-0.2W-0.2B-0.02Y(原子分数/%)),开展了750℃条件下不同应变速率的单轴拉伸、低周疲劳、疲劳-蠕变交互和蠕变试验,获得了相应试验条件下的试验数据和曲线,基于宏观唯象Chaboche黏塑性统一本构模型,采用Ohno-Wang修正项准确表征材料的循环硬化/软化行为。另外,为了准确模拟材料的加速蠕变阶段,在Chaboche黏塑性统一本构模型中耦合Kachanov损伤演化率,采用自适应的显式Euler法将微分形式的本构模型离散为差分方程组,并植入到有限元软件ABAQUS的用户材料子程序UMAT中,实现对高Nb-TiAl合金在不同试验条件下力学行为的仿真模拟。结果表明,采用考虑Ohno-Wang修正并耦合Kachanov损伤的Chaboche黏塑性统一本构模型能够准确模拟高Nb-TiAl合金不同应变速率的单轴拉伸、低周疲劳、疲劳-蠕变交互和蠕变行为,且预测精度较高,满足实际工程需要。
Uniaxial tensile,low cycle fatigue,fatigue-creep interaction and creep experiments of a novel high-Nb TiAl alloy（i. e. Ti-45 Al-8 Nb-0. 2 W-0. 2 B-0. 02 Y（atom fraction/%）） were conducted at 750 ℃ to obtain its tested data and curves. Based on Chaboche visco-plasticity unified constitutive model,Ohno-Wang modified non-linear kinematic hardening was introduced in Chaboche constitutive model to describe the cyclic hardening/softening,and Kachanov damage was coupled in Chaboche constitutive model to characterize the accelerated creep stage. The differential equations of the constitutive model discretized by explicit Euler method were compiled in to ABAQUS/UMAT to simulate the mechanical behavior of high-Nb TiAl alloy at different test conditions. The results show that Chaboche visco-plasticity unified constitutive model considering both Ohno-Wang modified non-linear kinematic hardening and Kachanov damage is able to simulate the uniaxial tensile,low cycle fatigue,fatigue-creep interaction and creep behavior of high-Nb TiAl alloy and has high accuracy.
出处
《航空材料学报》
EI
CAS
CSCD
北大核心
2018年第1期80-87,共8页
Journal of Aeronautical Materials
基金
国家自然科学基金-青年基金项目(51401195)
国家重点基础研究发展计划(973计划)(2011CB605501)
航空基金项目(2013ZF21014)
作者简介
董成利（1982-）,男,博士,高级工程师,主要从事航空发动机高温结构材料及部件强度、寿命评估与有限元数值仿真研究,（E-mail）dcldong@buaa.edu.cn.
