ABSTRACT

The present work describes the influence of underwater laser shock peening without coating (LSPwC) on selective laser melting manufactured meso-size (outside diameter ≤ 10 mm) helical gears. Five experiments were conducted using energies in the 200 mJ up to 1 J, while the spot size and overlap were kept constant as 1 mm and 90 %, respectively. Responses were measured and compared in terms of surface residual stresses, surface roughness, and microstructure of LSPwC-treated samples. Results show the development of significant compressive residual stresses in the root of the LSPwC processed helical gear, where it changes the state from tensile +45 MPa to compressive −421 MPa. Surface roughness has shown improvement, while volumetric material peak confirms the reduction by over 50%. Microstructure study was performed at the surface and by cross-section using scanning electron microscopy and electron backscatter diffraction analysis. The grain refinement and change in misorientation were observed, confirming plastic deformation.

摘要

目前的工作描述了水下无涂层激光冲击喷丸 (LSPwC) 对选择性激光熔化制造的中等尺寸（外径 ≤ 10 mm）斜齿轮的影响。使用 200 mJ 至 1 J 的能量进行了五次实验，同时光斑尺寸和重叠分别保持恒定为 1 mm 和 90%。对经 LSPwC 处理的样品的表面残余应力、表面粗糙度和微观结构进行了测量和比较。结果显示，LSPwC 加工的斜齿轮根部产生了显着的残余压应力，其状态从拉伸 +45 MPa 变为压缩 -421 MPa。表面粗糙度有所改善，而体积材料峰值证实减少了 50% 以上。使用扫描电子显微镜和电子背散射衍射分析在表面和横截面进行微观结构研究。观察到晶粒细化和取向差的变化，证实了塑性变形。