选择性激光熔化成形AlSi10Mg合金甲烷泵壳体开裂失效分析

Cracking Failure Analysis of AlSi10Mg Alloy Methane Pump Shell by Selective Laser Melting

某甲烷泵壳体采用AlSi10Mg合金粉末选择性激光熔化成形,即3D打印(three dimension printing)快速成形技术,但在成形后发现有贯穿轮廓的层间裂纹。通过采用光谱仪及电感耦合等离子体ICP检测材料化学成分、万能试验机检测力学性能、体视显微镜分析裂纹宏观形貌、场发射扫描电镜分析断口微观形貌、材料显微镜检测裂纹处及成形件基体的金相组织,结果表明,AlSi10Mg甲烷泵壳体激光成形件内腔表面裂纹实际为该铝合金壳体激光成形时的层间未熔合缺陷。其原因是激光振荡器不稳定导致功率过低和激光扫描速度过快。

A methane pump shell is formed by selective laser melting of AlSi10 Mg alloy powder,namely 3 D printing rapid prototyping technology.But the methane pump shell is found to have interlayer cracks running through the contour after forming.The chemical composition of the material was detected by spectrograph and inductively coupled plasma emission spectrometer(ICP),the mechanical properties was tested by universal testing machine,the macroscopic morphology of the crack was analyzed by stereomicrograph,the microstructure of the fracture was analyzed by field emission scanning electron microscope,and the microstructure of the crack and the matrix was detected by the material microscope.The results show that the crack on the inner cavity surface of AlSi10 Mg methane pump shell is actually the defect of interlayer unfusion during laser forming of the aluminum alloy shell.The reason is that the laser oscillator instability lead to low power and scanning speed is too fast.