Cu-Be/Cu层状非均质复合材料塑性变形行为的原位研究  

In-situ Study of the Plastic Deformation Behavior of Cu-Be/Cu Laminated Heterogeneous Composite

作　　者：唐延川 张欣磊 柳春林 焦海涛 刘德佳 胡勇[1,2] 赵龙志 Tang Yanchuan;Zhang Xinlei;Liu Chunlin;Jiao Haitao;Liu Dejia;Hu Yong;Zhao Longzhi(School of Materials Science and Engineering,East China Jiaotong University,Nanchang 330013,China;Nanchang Key Laboratory of Advanced Materials for Vehicles&Laser Additive Manufacturing,East China Jiaotong University,Nanchang,330013,China)

机构地区：[1]华东交通大学材料科学与工程学院,江西南昌330013 [2]华东交通大学载运工具先进材料与激光增材制造南昌市重点实验室,江西南昌330013

出　　处：《华东交通大学学报》2022年第3期99-109,共11页Journal of East China Jiaotong University

基　　金：国家自然科学基金项目(51701074,52065023);江西省自然科学基金项目(20202ACBL214015);江西省自然科学基金项目(20202ACB211002)。

摘　　要：将层状非均质构型复合化设计思想用于提高Cu-Be合金强韧性,采用真空热压复合、热轧及热处理的方式制备了CuBe/Cu层状非均质复合材料。对复合材料显微组织、显微硬度及拉伸性能进行了测试分析,利用SEM下原位拉伸结合DIC技术,研究了复合材料塑性变形中各金属层组织演变、应变分配及断裂行为。结果表明:Cu-Be/Cu层状非均质复合材料由粗晶Cu层(平均晶粒尺寸115.3μm)和细晶Cu-Be层(平均晶粒尺寸17.4μm)组成,Cu-Be层显微硬度约为Cu层5倍,复合材料抗拉强度介于两种金属组元之间,但伸长率远高于Cu-Be合金、与Cu接近。复合材料塑性变形过程中,Cu-Be层主要通过晶粒转动方式协调应变,而Cu层主要通过晶内单系滑移方式协调应变;塑性变形初期,应变集中首先出现在Cu-Be/Cu界面附近,随后应变集中可通过界面传递至两侧金属层内部。复合材料断裂过程中,首先在Cu-Be层中晶界处萌生微裂纹,并沿晶界扩展;当裂纹扩展至Cu-Be/Cu界面时,发生明显偏折,裂纹在Cu层内表现为穿晶扩展,界面附近Cu层呈现准解理断裂特征。The laminated heterogeneous configuration design was applied to improve the strength and toughness of the Cu-Be alloy. The Cu-Be/Cu laminated heterogeneous composite by vacuum hot pressing bonding, hot rolling and subsequent heat treatment was successfully prepared. The microstructure, microhardness and tensile properties of the composites were investigated. During the plastic deformation of the composite, the microstructure evolution, strain distribution and fracture behavior of different metal layers were characterized by in-situ tension under SEM combined with DIC technique. The results show that the Cu-Be/Cu laminated heterogeneous composite is composed of coarse grained Cu layers(with average grain size of 115.3 μm) and fine grained Cu-Be layers(with average grain size of 17.4 μm). The microhardness of Cu-Be layers is approximately 5 times higher than that of Cu layers. The ultimate tensile strength of the composite is between that of the two metals, but the ductility of the composite is close to that of the Cu, which is much higher than that of the Cu-Be alloy. During the plastic deformation of the composite, the strain of the Cu-Be layers is mainly coordinated by grain rotation,while the strain of the Cu layers is mainly coordinated by single slip inside the grains. At the initial stage of plastic deformation, the strain concentration first appears in the vicinity to the Cu-Be/Cu interfaces. Then the strain concentration can be transmitted into the metal layers through the interfaces. During the fracture of the composite, the microcracks initiate at the grain boundaries of the Cu-Be layers and propagate along the grain boundaries. Significant crack deflection phenomenon occurs when the cracks propagate to the Cu-Be/Cu interface. The crack propagates transgranular in the Cu layers. The morphology of the fracture of the Cu layer present the characteristics of quasi-cleavage fracture.

关 键 词：层状非均质复合材料 强韧化 原位拉伸 塑性变形行为 应变分配 

分 类 号：TG335.5[金属学及工艺—金属压力加工]