激光修复TC4钛合金锻件的工艺和性能稳定性研究

Study on Stabilities of Techniques and Properties of Laser Repairing TC4 Alloy Wrought Components

航空用结构锻件加工过程中容易出现"断刀"和内部冶金缺陷暴露这两类情况,通过提炼生产实践中出现的各类缺陷特征,把误加工损伤缺陷归纳为槽缺陷、面缺陷和体缺陷三种典型损伤形式。采用激光修复技术,以TC4钛合金结构锻件为基材,以TC4钛合金粉末为熔覆材料,制备了槽、面、体三种修复试样。同一工艺参数同一缺陷类型条件下,每组试样的显微组织相似,无明显变化。随着有效热输入的增加,热影响区的深度增加,其宽度在0.3～0.74 mm之间。考察了不同工艺参数下激光修复区的外形尺寸(激光修复区的高度和宽度),结果表明在一定参数范围内修复区的几何尺寸稳定性好。采用统计学原理对拉伸性能测试结果进行了数据分析,结果表明拉伸性能以95%的置信度,99%存活率的估计与真值的相对误差不超过±5%,力学性能稳定。

The two kinds of defects called as ＂machining tool broken＂ and metallurgy flaw emerged are easy to be encountered in the manufacturing process of aviation structural wrought. Aimed at repairing the two kinds of defects, three typical defect forms were induced to groove defection, surface defection, and body defection. In the paper three groups of samples named as groove repair, surface repair and body repair were prepared with as-forged TC4 alloy as the substrates, the TC4 powder as cladding materials. The microstructures of each group sample are similar to each other and there are no evident changes with the laser repair parameters changing. With the increasing of effective heat input, the depth of heat affected zone （HAZ） aggrandizes. The width of HAZ is between 0.3-0.74mm. Furthermore, the height and width of the repair zone were investigated, the results show that the geometry stabilities are good in a definite parameters range. The statistics theory was adopted to analyze the tensile properties, the results show that the mechanical properties of laser repair samples have 99% livability with the condition of r=95%, δ=5%. That means the mechanical properties is stable too.