摘要
以激光快速成型FGH96粉末高温合金为研究对象,采用光学及扫描电子显微镜对沉积态与固溶时效后的显微组织结构进行表征,并分析微观组织与缺陷的特征及形成原因;对两种状态试样进行室温拉伸试验,对比二者的力学性能,并采用体式显微镜及扫描电子显微镜对断口进行观察,分析断裂特征。结果显示:激光快速成型FGH96沉积态组织主要为垂直于熔覆界面的柱状晶,晶内为细密树枝晶,碳化物聚集于枝晶间;重熔区内枝晶结构明显粗大,显示为白亮色;激光快速成型FGH96材料中的主要缺陷为微裂纹,沉积态微裂纹存在于枝晶间,并沿晶界扩展;固溶时效后为典型沿晶裂纹;固溶时效后,FGH96中碳化物减少,组织更加均匀,晶粒尺寸减小,力学性能较沉积态有所提高。
The microstructures of the as-deposited and solution-aging of the laser rapid prototyping（LRP） FGH96 superalloy were observed by using optical microscopy（ OM） and scanning electron microscopy（SEM）. The character and formation reason of the microstructure and defects of the two samples were also analyzed. Room temperature tension tests were conducted in order to compare the mechanical property of the two condition samples. The rupture characters were analyzed based on the observation of the fractures by using OM and SEM. The results indicate that the main structure of the as-deposited FGH96 is typical directional solidification columnar structure which is perpendicular to the melting interface. The fine dendrite exists within the columnar grain,and the carbides segregate in the interdendrite. The dendrites become coarse in the re-melting region,displaying a bright white color. After solution-aging,the carbides decrease and the microstructure is more homogenous. The main defects of the LRP FGH96 are intergranular cracks,both in the as-deposited and solution-aging samples. The mechanical property of the sample after solution-aging has improved with the as-deposited one.
出处
《失效分析与预防》
2016年第2期124-128,共5页
Failure Analysis and Prevention
