摘要
以高速列车常用的A7N01S-T5铝合金型材焊接热影响区为研究对象,分析析出相的SEM组织及化学成分,采用超景深显微镜观察不同时间节点腐蚀疲劳裂纹萌生过程,并统计分析点蚀坑的面积及最大径长。结果表明,热影响区的腐蚀面积率、腐蚀速率、蚀坑最大径长均随着试验时间的增加而增加,腐蚀坑主要沿着挤压方向分布的大颗粒、富含Fe的二相粒子周围萌生,在交变应力的促进作用下,热影响区腐蚀疲劳裂纹在腐蚀坑最大径向方向沿着挤压方向萌生、扩展。
By taking the heat .affected zone（ HAZ ）of a typical aluminum alloy profile A7N01S-T5 as the research object oil the high- speed train,the microstructures and chemical composition of precipitates were analyzed by the SEM,corrosion fatigue crack initiation process under different time nodes were observed by microscope of super depth of fiehl,the statistical infonnation oil the area and maximum of corrosion pits were researched. The results showed that corrosion area,corrosion rate,the maximum of diameter were increased with experiment time,corrosion pits initiated near the large particles or precipitates including Fe which were distributed along extrusion direction,under the promotion of alternating stress,corrosion fatigue cracks in the HAZ initiated and propagated on the direction of maximum diameter along the extrusion direction.
出处
《电焊机》
2015年第5期107-111,共5页
Electric Welding Machine
基金
国家科技支撑计划项目(2013BAG24B02)
国家863项目(2012AA112001)
