激光沉积修复BT20合金试验研究

Experimental study on laser deposition repair BT20 alloy component

采用激光沉积技术对BT20钛合金锻件加工超差及服役损伤进行修复,对修复过程中气孔和熔合不良等缺陷的形成进行了原因分析,并采用了优化工艺参数,对激光熔池施加超声外场等手段,获得无缺陷的修复试样。考察了试样的微观组织和主要合金元素的分布,测量了激光沉积层的显微硬度。结果表明:优化工艺参数后得到的修复组织和基体形成致密的冶金结合,而施加超声外场使修复区的气孔率明显下降;修复试样整体无合金元素的偏析,显微硬度分布从基材到修复区呈递增趋势。

Researches on the laser deposition repair of BT20 alloy forgings having defects mis-machined or damage were investigated, the reasons of occurring defects such as gas porosities and ill bonding in the repaired zone were analyzed. And flawless samples were obtained through optimizing laser process parameters and introducing the ultrasonic vibration into laser deposition repair system. The microstructure characteristic of laser deposition repair component and distribution of main alloy elements were investigated, and the microhardness of the laser deposition layer was tested. The results indicate that there is a dense metallurgical bond between the repaired zone and the substrate with the optimized process parameters. While the gas porosities ratio of the laser deposition layer is decrease obviously through introducing the ultrasonic vibration to the repaired system. The component elements are unifomly distributed without fluctuation and segregation in the whole repaired sample. Distribution of microhardness from the substrate to the repaired zone showes an increasing trend.