激光沉积修复TA15钛合金断裂韧度研究

Fracture Toughness Properties of Laser Deposited Repair TA15 Titanium Alloy

摘要:

采用激光沉积修复技术对预损伤TA15钛合金锻件进行修复,研究基材、成形试样、体修复试样以及面修复试样的断裂韧度。采用光学显微镜和扫描电子显微镜分析试样微观组织、断裂表面以及纵截面形貌。结果表明：基材呈现双态组织,修复区呈现网篮组织,热影响区表现为从双态组织到网篮组织的转变。成形试样、体修复试样以及面修复试样的断裂韧度均低于基材,分别达到基材的76.4%、81.0%、83.1%。断裂韧度随屈强差的增大而增大,当屈强差增大程度相同时,修复试样断裂韧性的提高比基材更明显且成形试样增加程度最显著。裂纹在集束内部沿直线扩展,遇到取向不同的α片层集束时,发生偏转并沿着α片层集束的边界扩展,且集束尺寸越小偏转现象越严重。

Abstract:

The technology of laser deposited repair was used to repair TA15 alloy forgings,and the fracture toughness of substrate,shaped component,body-repaired sample and surface-repaired sample were investigated. Microstructure, fracture surface and longitudinal section morphology of sample were examined by OM and SEM.The results show that the substrate presents duplex microstructure, the repaired zone presents basket weave, and the heat-affected zone shows continuous microstructure transition from duplex microstructure to basket weave.The fracture toughness of shaped component,body-repaired sample and surface-repaired sample are lower than that of substrate, which are 76.4%, 81.0% and 83.1% of substrate respectively.The fracture toughness increases with the increase of the yield difference. When the increase of the yield difference is the same, the fracture toughness of repaired samples increases more significantly than that of substrate, and the increase of the shaped component is the most significant.The cracks expand in a straight line inside the cluste. When the α lamellar cluster with different orientations is encountered, the crack deflects and propagates along the boundary of α lamellar cluster. The smaller the cluster size is, the more serious the deflection is.