硬钎焊温度对Cu-Cr-Zr合金组织和力学性能的影响  

Effect of Brazing Temperature on Microstructure and Mechanical Properties of Cu-Cr-Zr Alloy

作　　者：董博文 钟素娟 裴夤崟 吕登峰 龙伟民 Dong Bowen;Zhong Sujuan;Pei Yinyin;Lv Dengfeng;Long Weimin(State Key Laboratory of Advanced Brazing Filler Metals&Technology,Zhengzhou Research Institute of Mechanical Engineering Co.,Ltd,Zhengzhou 450001,China)

机构地区：[1]郑州机械研究所有限公司新型钎焊材料与技术国家重点实验室,河南郑州450001

出　　处：《稀有金属材料与工程》2020年第12期4081-4087,共7页Rare Metal Materials and Engineering

基　　金：International S&T Cooperation Program of China(2016YFE0201300)。

摘　　要：以时效硬化后的Cu-1.04Cr-0.16Zr合金为研究对象,采用扫描电镜、拉伸试验机、显微硬度计、体视显微镜研究了不同硬钎焊温度(600~800℃)下的Cu-1.04Cr-0.16Zr母材的组织、拉伸性能、显微硬度及断口特征,并在此基础上分析了Cu-1.04Cr-0.16Zr合金的高温软化机制。结果表明:Cu-1.04Cr-0.16Zr合金的抗拉强度和显微硬度随钎焊温度的升高而降低,初始抗拉强度为477.32 MPa,延伸率为40.13%,显微硬度为1517MPa,当钎焊温度为600℃时,Cu-1.04Cr-0.16Zr合金抗拉强度稍有降低,显微硬度基本不变,表现出良好的抗软化性能;当钎焊温度为650℃时,Cu-1.04Cr-0.16Zr合金开始发生部分再结晶,大等轴晶边界出现一些细小、无畸变的等轴晶粒,晶粒尺寸为2~7μm,析出相对晶界的钉扎作用开始减弱,抗拉强度和显微硬度大幅下降;随着钎焊温度的升高,Cu-1.04Cr-0.16Zr合金进一步软化,Cu-1.04Cr-0.16Zr合金内部出现大量的退火孪晶;Cu-1.04Cr-0.16Zr合金在硬钎焊温度条件下均出现颈缩现象,并存在明显的塑性扩展区,随着钎焊温度的升高,断面收缩率逐渐增大,韧窝沿拉伸方向伸展长大,表现出很好的塑性。在满足钎焊接头各项性能的条件下,可采用熔化温度较低的钎焊材料,避免Cu-1.04Cr-0.16Zr合金出现软化现象。Cu-Cr-Zr alloys are kinds of copper alloys with high strength and high conductivity,usually appl ied to the manufacturing of key parts in complex environment such as high temperature and wear resistance.In this research,we studied the microstructure,tensile properties,microhardness,and fracture characteristics of Cu-1.04 Cr-0.16 Zr alloy at different brazing temperatures(600~800℃)by scanning electron microscope,cupping machine,micro-hardness tester,and stereomicroscope.On this basis,the softening mechanism of Cu-1.04 Cr-0.16 Zr alloy at high temperature was analyzed.The results show that the ultimate tensile strength(UTS)and microhardness of alloys decrease with the increase of brazing temperature.The UTS,elongation,and microhardness of the samples are about 477.32 MPa,40.13%and 1517 MPa,respectively.When the brazing temperature of Cu-1.04 Cr-0.16 Zr alloy is 600℃,the UTS decreases slightly whereas the microhardness is basically unchanged,and they show good softening resistance.Partial recrystallization starts to occur in the microstructure of Cu-1.04 Cr-0.16 Zr alloy when the brazing temperature is 650℃.Some fine and undistorted equiaxed grains appear at the boundary of large equiaxed grains,whose size is 2~7μm.The pinning effect of precipitates on grain boundary begins to weaken.The UTS and microhardness decrease significantly.The samples are further softened with the increase of brazing temperature,and a lot of annealing twins appear in the microstructure of Cu-1.04 Cr-0.16 Zr alloy.Cu-1.04 Cr-0.16 Zr alloy has necking phenomenon and obvious plastic expansion zones after brazing.The shrinkage of cross section increases gradually with the increase of brazing temperature.The dimples grow along the tensile direction,and Cu-1.04 Cr-0.16 Zr alloy shows good plasticity.In summary,under the condition of satisfying the properties of the brazed joints,the softening of Cu-Cr-Zr alloys can be avoided by brazing filler metals with lower melting temperature.

关 键 词：硬钎焊 再结晶 抗拉强度 显微硬度 

分 类 号：TG454[金属学及工艺—焊接] TG146.11[一般工业技术—材料科学与工程]