激光选区熔化成形工艺对TA15钛合金内部缺陷与力学性能的影响

Effect of selective laser melting process on internal defects and mechanical properties of TA15 titanium alloy

利用激光选区熔化(Selective laser melting,SLM)成形技术制备TA15钛合金,通过光学显微镜(Optical microscope,OM)、扫描电镜(Scanning electron microscope,SEM)和室温拉伸等研究了激光功率和扫描速度对SLM成形TA15钛合金内部缺陷与力学性能的影响规律。结果表明:在低激光功率(100~125 W)、高扫描速率(1200~1600 mm/s)区域,激光能量密度较低,合金内部缺陷主要为不规则形状的缺陷;在高激光功率(150~200 W)、低扫描速度(800~1000 mm/s)区域,激光能量密度过高,合金内部缺陷主要为规则球形缺陷。规则球形缺陷的存在会导致合金塑性显著降低、对强度影响较弱;而不规则未熔合缺陷的存在会显著降低合金强度和伸长率。TA15钛合金的最佳工艺参数:激光功率为200 W、激光扫描速度为1600 mm/s时,成形合金拉伸强度为(1291±4.2)MPa,断裂伸长率为(8.5±0.5)%。

TA15 titanium alloy was fabricated using selective laser melting(SLM),and the focus was on investigating the impact of laser power and scanning speed on internal defects and mechanical properties.Various characterization techniques were employed,including optical microscopy(OM),scanning electron microscopy(SEM)and room-temperature tensile testing.The results reveal that the parameters of low laser power(100-125 W)and high scanning speed(1200-1600 mm/s)result in predominantly internal defects with irregular shapes,attributable to insufficient energy input during the SLM process.On the other hand,high laser power(150-200 W)and low scanning speed(800-1000 mm/s)result in regular spherical defects within the alloy due to relatively high energy input.The presence of irregular shapes or unfused defects in the alloy can significantly reduce its strength and elongation.By employing laser power of 200 W and scanning speed of 1600 mm/s,the SLM process achieves optimized parameters and results in tensile strength of(1291±4.2)MPa and elongation after fracture of(8.5±0.5)%.