In cold spray additive manufacturing (CSAM), the severe plastic deformation of the input powder particles leads to an accumulation of residual stresses, the magnitude of which is affected by process conditions. In the current study, the effects of traverse speed and powder feed rate on the residual stress state were investigated in commercially pure titanium cylinders produced by CSAM. Residual stress measurements were made in a grid pattern covering the 2D cross section using the KOWARI neutron diffractometer at ANSTO, Australia, and selected results were validated using the contour method. It was found that the thermal effect was dominant on the residual stress state generating a tensile state near the inner and outer surfaces of the cylinder walls while compressive residual stresses tend to accumulate in the center of the wall. The residual stresses were dominated by thermal stresses at low traverse speed, while peening becomes more critical at high traverse speeds. Increasing the powder feed rate increased the magnitude of the residual stresses. High traverse speeds and low feed rates are beneficial for producing 3D parts by CSAM. However, slow traverse speeds are more detrimental than high feed rates for a given layer thickness.

中文翻译：

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冷喷涂增材制造空心钛圆柱的残余应力

在冷喷涂增材制造 (CSAM) 中，输入粉末颗粒的严重塑性变形会导致残余应力的积累，其大小受工艺条件的影响。在目前的研究中，在由 CSAM 生产的商业纯钛圆柱体中研究了横向速度和粉末进料速率对残余应力状态的影响。使用澳大利亚 ANSTO 的 KOWARI 中子衍射仪在覆盖 2D 横截面的网格图案中进行残余应力测量，并使用轮廓法验证选定的结果。结果表明，热效应在残余应力状态下占主导地位，在气缸壁的内外表面附近产生拉伸状态，而压缩残余应力倾向于在壁中心积聚。残余应力在低移动速度下由热应力主导，而在高移动速度下喷丸变得更加关键。增加粉末进料速率会增加残余应力的大小。高移动速度和低进给速度有利于通过 CSAM 生产 3D 零件。然而，对于给定的层厚，慢速移动比高进给速度更有害。