There has been considerable interest in the application of cold gas dynamic spray (CGDS) to deposit nickel-based superalloy coatings for the repair and development of high-value components that operate under extreme environmental conditions. The CGDS process introduces residual stresses in the coating layers, but inherently effects the subsurface of the substrate in a similar manner. The present study investigates the effect of low temperature range heat treatments (100-400 °C) on the residual stress of CGDS Inconel® 718 deposited onto a presolution-treated Al7075-T651 substrate. High spatial resolution nondestructive residual stress measurements were carried out via neutron diffraction on both the CGDS deposit and substrate. The low temperature range heat treatments displayed a significant effect on both the substrate and coatings. Residual stress relaxation was exhibited in coatings that were heat-treated at the lowest temperature, whereas an increased heat treatment temperature displayed an opposite effect, increasing both the compressive residual stress in the IN718 coating and the residual tensile stress in the substrate. It is proposed the difference in thermal expansion coefficient of the two materials was the main factor responsible for the residual stresses. The effect of post-heat treatment on coating microhardness and porosity is also presented.

中文翻译：

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低温热处理对冷气动态喷涂Inconel 718涂层中子衍射残余应力的影响

应用冷气动态喷涂 (CGDS) 来沉积镍基高温合金涂层，以修复和开发在极端环境条件下运行的高价值部件，这引起了极大的兴趣。CGDS 工艺会在涂层中引入残余应力，但会以类似的方式固有地影响基材的下表面。本研究调查了低温范围热处理 (100-400 °C) 对沉积在经过分辨率处理的 Al7075-T651 基板上的 CGDS Inconel® 718 残余应力的影响。通过中子衍射对 CGDS 沉积物和基底进行高空间分辨率无损残余应力测量。低温范围热处理对基材和涂层均显示出显着影响。在最低温度下热处理的涂层中表现出残余应力松弛，而提高热处理温度显示出相反的效果，增加了 IN718 涂层中的压缩残余应力和基材中的残余拉伸应力。提出两种材料的热膨胀系数的差异是造成残余应力的主要因素。还介绍了后热处理对涂层显微硬度和孔隙率的影响。提出两种材料的热膨胀系数的差异是造成残余应力的主要因素。还介绍了后热处理对涂层显微硬度和孔隙率的影响。提出两种材料的热膨胀系数的差异是造成残余应力的主要因素。还介绍了后热处理对涂层显微硬度和孔隙率的影响。