TC17钛合金激光增材修复组织与性能

Microstructure and properties of laser additive repaired TC17 titanium alloy

针对TC17钛合金零部件边缘损伤修复需求,开展激光增材修复工艺研究,通过正交试验法优化工艺参数,获得熔深较小且无缺陷修复试样;研究了修复后材料的显微组织、硬度以及摩擦磨损性能。结果表明:TC17钛合金激光增材修复宏观组织由柱状晶和等轴晶所组成,不同沉积层内部显微组织为分布不均匀的细小α+β相所组成的特殊双态组织;由于多层沉积热循环的影响,修复区顶部至底部α相含量逐渐增多,且组织逐渐均匀化。基体显微组织为α/β组成的双态组织,相比于基体,热影响区中等轴α相发生了溶解,晶内组织为分布均匀的近网篮组织。与基体相比,热影响区平均显微硬度提高了3.5%,修复区顶部、中部、底部显微硬度分别比基体高5.4%、8.9%、10.2%;修复区的耐磨性高于基体,且修复区顶部至底部,耐磨性比基体高23%、69%、77%。

According to the requirements of edge damage repair of TC17 titanium alloy parts,the laser additive repair process was studied.Orthogonal test was carried out to optimize the process parameters,and the repaired samples with low penetration depth and no defects were obtained.The microstructure,hardness and friction wear properties of the repaired material were studied.The results show that the microstructure of the laser additive repaired TC17 titanium alloy consists of columnar crystals and equiaxed crystals,and the internal microstructure of different layers is a special two-state microstructure composed of fineα+βphases with uneven distribution.Due to the influence of multilayer sedimentary thermal cycle,the content ofαphase gradually increases from the top to the bottom of the repaired area,and the microstructure gradually homogenizes.The matrix microstructure isα/βbistate structure.Theαphase in the middle axis of the heat affected zone dissolves compared with the matrix,and the intracrystalline microstructure is homogeneous basket-like structure.Compared with the matrix,the average microhardness of the heat affected zone increased by 3.5%,and the microhardness of the top,middle,and bottom of the repaired zone increased by 5.4%,8.9%,and 10.2%,respectively.The wear resistance of the repaired zone is higher than that of the matrix,and the wear resistance of the repaired zone from the top to the bottom is 23%,69%and 77%higher than that of the matrix.