铸态Zr-Co-(Al)合金的加工硬化行为和表面裂纹扩展  

Work hardening behavior and surface crack propagation of as-cast Zr-Co-(Al)alloys

作　　者：董洪峰[1] 杨寅臻 孟凡莹[1] 李培友[1] 刘亚玲 张薇 王琳 武俊霞 DONG Hong-feng;YANG Yin-zhen;MENG Fan-ying;LI Pei-you;LIU Ya-ling;ZHANG Wei;WANG Lin;WU Jun-xia(School of Materials Science and Engineering,Shaanxi University of Technology,Hanzhong 723001,China)

机构地区：[1]陕西理工大学材料科学与工程学院,陕西汉中723001

出　　处：《材料热处理学报》2022年第8期86-92,共7页Transactions of Materials and Heat Treatment

基　　金：陕西省教育厅专项科研计划项目(20JK0563);陕西省自然科学基础研究计划青年项目(2020JQ-870)。

摘　　要：采用X射线衍射仪、光学显微镜、电子万能试验机和扫描电镜等研究了铸态Zr-Co-(Al)合金的微观组织、加工硬化行为和表面裂纹扩展。结果表明:Zr_(50)Co_(50)和Zr_(49)Co_(49)Al_(2)合金的组织均是由B2 Zr_(50)Co_(50)相组成,少量Al元素的添加并没有改变合金的相组成,说明少量Al原子固溶到基体Zr_(50)Co_(50)相的颗粒内。与Zr_(50)Co_(50)合金相比,Zr_(49)Co_(49)Al_(2)合金的塑性变形抗力小于Zr_(50)Co_(50)合金的塑性变形抗力,Zr_(49)Co_(49)Al_(2)合金的塑性变形能力较好,利于冷加工变形。在弹塑性区和塑性区,加工硬化倾向于晶粒和晶界之间的同步,导致Zr_(50)Co_(50)合金的Δn值较小;当晶粒和晶界的变形非同步发生时,将导致Zr_(49)Co_(49)Al_(2)合金的Δn值较大。当大晶粒作用在两个小晶粒时,位于两个小晶粒晶界处的应力集中引起晶界处裂纹萌生并扩展。Microstructure,work hardening behavior and surface crack propagation of as cast Zr-Co-(Al)alloys were studied by means of X-ray diffractometer,optical microscope,electronic universal testing machine and scanning electron microscopy.The results show that the microstructure of the Zr_(50)Co_(50) and Zr_(49)Co_(49)Al_(2) alloys is composed of B2 Zr_(50)Co_(50) phase.The addition of a small amount of Al element does not change the phase composition of the alloy,indicating that a small amount of Al atoms are dissolved into the particles of Zr_(50)Co_(50) phase in the matrix.Compared with the Zr_(50)Co_(50) alloy,the plastic deformation resistance of the Zr_(49)Co_(49)Al_(2) alloy is less than that of the Zr_(50)Co_(50) alloy,and the plastic deformation ability of the Zr_(49)Co_(49)Al_(2) alloy is better,which is conducive to cold working deformation.In the elastic-plastic zone and plastic zone,work hardening tends to be synchronous between grains and grain boundaries,resulting in the smallΔn value of the Zr_(50)Co_(50) alloy.When the deformation of grain and grain boundary occurs asynchronously,theΔn value of the Zr_(49)Co_(49)Al_(2) alloy will be large.When the large grain acts on two small grains,the stress concentration at the grain boundary of the two small grains causes the crack initiation and propagation at the grain boundary.

关 键 词：Zr-Co合金 加工硬化 形变强化指数变化率 裂纹扩展 

分 类 号：TG146.4[一般工业技术—材料科学与工程]