激光近净成形TC21钛合金的组织与性能

Microstructure and properties of laser near net formed TC21 titanium alloy

对TC21钛合金进行了激光近净成形制备,采用光学显微镜和扫描电镜进行了组织分析,同时对沉积态和双重退火态试样进行了拉伸性能测试。结果表明,激光近净成形TC21钛合金组织呈外延生长特性,为沿沉积高度方向增加的柱状β晶,微观上β晶内为细密的网篮组织,比锻件显微组织更细小;室温拉伸性能与锻件实测值相比,强度相当,塑性略低,但均高于锻件标准要求;拉伸断裂呈现为不同形状和大小韧窝的韧性特征。

TC21 titanium alloy sample was prepared by laser near net forming , and microstructure and properties of deposited and double annealed specimens were investigated by OM , SEM and tensile properties test .The results show that the microstructure of laser near net formed specimen has a epitaxial growth characteristics that the βcolumnar crystal grows along the height direction of deposition .The microstructure of βcolumnar crystal appear as basket-weave and smaller than forging matrix .The tensile strength of the alloy is equal to strength of forging actual measurement at room temperature , the plasticity is lower than that of the forging , but all over the forging standard . There are a lot of dimples with different shape and size distributed on tensile fracture , thus is ductile fracture .