原位TiB_(2)颗粒增强7075铝基复合材料在不同应力状态下的韧性断裂行为  

Ductile fracture behavior of in situ TiB_(2) particle reinforced 7075 aluminum matrix composite in various stress states

作　　者：王涵 章海明 崔振山[1] 陈哲 陈东[1] Han WANG;Hai-ming ZHANG;Zhen-shan CUI;Zhe CHEN;Dong CHEN(School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学材料科学与工程学院,上海200240

出　　处：《Transactions of Nonferrous Metals Society of China》2023年第8期2272-2286,共15页中国有色金属学报（英文版）

基　　金：the financial support from the National Natural Science Foundation of China(No.52075328);Shanghai Rising-Star Program,China(No.20QA1405300).

摘　　要：采用力学试验、微观表征和数值模拟研究原位TiB_(2)颗粒增强7075铝基复合材料在不同应力状态下的断裂行为。设计4组拉伸试样、1组剪切试样和1组压缩试样,并对这6组试样进行力学实验。通过原位应变测试和有限元模拟研究6组试样在变形过程中的应变分布。对6组试样的断口形貌进行表征,分析其在不同应力状态下的损伤演化机制。研究发现:该材料的主要断裂机制为界面脱粘和颗粒断裂,表现为高应力三轴度下的拉伸断裂和低应力三轴度下的剪切断裂。在拉伸断裂条件下,形核空洞的体积在最大主应力的作用下增大;在剪切断裂条件下,空洞的形状在最大剪应力作用下变化明显,而体积变化不明显。基于实验揭示的断裂机理,提出一种考虑最大主应力和最大剪应力的韧性断裂准则,该准则可以预测该复合材料在不同应力状态下的断裂曲面。与改进的Mohr−Coulomb、Lou−Yoon−Huh、Hu和Mu模型的对比分析表明,新模型能更准确地预测铝基复合材料的韧性断裂行为。The fracture behavior of an in situ TiB_(2) particle reinforced 7075 aluminum matrix composite in various stress states was investigated by mechanical tests,microscopic characterization,and numerical simulations.Four sets of tensile specimens,one group of shear specimens,and one group of compression specimens were designed,and mechanical experiments were conducted on these six groups of specimens.The strain distributions of the six groups of specimens during deformation were investigated by in situ strain testing and finite element simulation.The fracture morphology of the specimens was characterized to analyze the damage mechanism in different stress states.It was found that the fracture mechanism of the material is mainly interfacial debonding and particle fracture,manifested as tensile fracture under high stress triaxiality and shear fracture under low stress triaxiality.For the tensile fracture,the nucleated voids grew with the maximum principal stress;for the shear fracture,they showed significant shape change with the maximum shear stress but little volume change.Based on the fracture mechanisms uncovered by the experiments,a modified ductile fracture criterion,considering the influence of both the maximum principal stress and maximum shear stress,was developed for the composite.Comparison with the modified Mohr−Coulomb,Lou−Yoon−Huh,Hu,and Mu models shows that the proposed model can predict the ductile fracture behavior of the aluminum matrix composites more accurately.

关 键 词：铝基复合材料 韧性断裂准则 界面脱粘 颗粒断裂 

分 类 号：TB333[一般工业技术—材料科学与工程]