工艺参数对Ti48Al2Cr2Nb合金单道激光沉积组织的影响

Effect of Process Parameters on Microstructure of Ti48Al2AlCr2Nb Alloy Made by Single Laser Metal Deposition

通过激光金属沉积成型技术(LMD)技术制备了Ti48Al2Cr2Nb合金试样,研究了不同工艺条件下试样的表面形貌、几何特征、裂纹、显微组织和显微硬度。结果表明,激光功率对沉积层的形貌影响最大,随着激光功率的增加,沉积层裂纹逐渐减少,熔宽逐渐增大;稀释率也随着激光功率的增大而增大,激光功率从2000 W增加至3000 W时,稀释率从0.334%增加到0.764%。同时,随着激光功率的增大,显微组织从柱状晶向等轴晶转变,沉积层显微组织主要由α_(2)相和γ相组成。在不同工艺参数条件下,显微组织中织构也发生变化。当激光功率增大时,显微硬度减小,当激光功率达到3000 W时,硬度值降为386.3 HV。

Ti48Al2Cr2Nb alloy samples were prepared by laser metal deposition(LMD)technology.The surface morphology,geometric characteristics,cracks,microstructure and microhardness of the samples were studied under different processing conditions.The results show that the laser power has the greatest influence on the morphology of the sedimentary layer.With the increase of the laser power,the crack of the sedimentary layer decreases and the welding width increases gradually.The dilution rate also increases with the increase of laser power.When the laser power increases from 2000 W to 3000 W,the dilution rate increases from 0.334%to 0.764%.At the same time,with the increase of laser power,the microstructure changes from columnar crystal to equiaxed crystal,and the microstructure of the sedimentary layer is mainly composed of α_(2) and γ phases.Under the condition of different processing parameters,the texture of the microstructure also changed.When the laser power increases,the microhardness decreases,and when the laser power reaches 3000 W,the hardness value decreases to 386.3 HV.