摘要
通过光学显微镜、扫描电镜和硬度测试等分析手段研究了在1250℃下扩散保温不同时间对W元素在Ti Al合金中扩散行为的影响。结果表明:试样在1250℃下进行扩散不同时间后,渗层界面处连接良好,可观察到明显的冶金结合。扩散层厚度随扩散时间的延长而增加,扩散4 h后可得到约15μm厚的渗层,扩散24 h后可得到约45μm厚的渗层,此外较长的扩散时间(24 h)可显著改善界面处的裂纹和气孔等缺陷。W在Ti Al合金中的扩散机制主要为置换和空位扩散,且W和Ti的原子半径和热膨胀系数等存在差异,使得晶格畸变的出现并进一步阻碍了W元素的扩散。显微硬度试验结果表明W在Ti Al合金中进行扩散,可以增强Ti Al合金的硬度,且硬度值随W含量的增大而增大。
Effect of holding time on diffusion behavior of tungsten in Ti Al alloy under 1250℃was studied by means of OM,SEM,and hardness test.The results show that,the interface between specimens have good combination after diffusion at 1250℃for different time,which shows obvious metallurgical bonding.And the thickness of diffusion layers increases with increasing time,thus the thickness of diffusion layer after diffusion for 4 h is about 15μm,and that for 24 h is about 45μm.In addition,the defects such as cracks and pore at the interface can be inhibited by prolonging diffusion time(24 h).The replacement and vacancy diffusion are the main diffusion mechanisms of tungsten in the Ti Al alloy,and the W and Ti atoms have some difference on atomic radius and coefficient of thermal expansion,which makes the lattice distort and furtherly prohibits the diffusion of W element.The results of hardness test show that,after diffusion of tungsten in the Ti Al alloy,the hardness of Ti Al alloy is reinforced,and the value increases with the increase of W contont.
作者
黄庆奕
易元
Huang Qingyi;Yi Yuan(AVIC Chengdu Aircraft Industry(Group)Co.,Ltd.,Chengdu Sichuan 610091,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2020年第11期94-98,共5页
Heat Treatment of Metals
关键词
钛铝合金
扩散机理
扩散连接
钨
titanium aluminum alloy
diffusion mechanism
diffusion bonding
tungsten
