The Elastic Modulus of Cold Spray Coatings: Influence of Inter-splat Boundary Cracking
The Elastic Modulus of Cold Spray Coatings: Influence of Inter-splat Boundary Cracking
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冷喷涂层的弹性模量：板间边界裂纹的影响
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
S. Kumar
中科院分区：
文献类型：
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作者：
G. Sundararajan;N. M. Chavan;S. Kumar
众所周知，与相同成分的散装材料相比，冷喷涂涂层表现出显着较低的弹性模量。还观察到冷喷涂涂层的热处理导致涂层的弹性模量显着增加。为了检查板间裂纹的存在是否是导致上述行为的原因，使用冷喷涂技术将粉末形式的各种金属材料（铜、银、锌、铌、钽、钛和 316L 不锈钢）沉积在低碳钢基材上。这些涂层在涂覆状态和热处理状态下的孔隙率、板间边界开裂程度、硬度和弹性模量均已得到表征。结果表明，涂层的弹性模量明显低于本体值，并且涂层的热处理持续增加其弹性模量值。研究表明，冷喷涂层弹性模量的降低与板间边界裂纹的程度有关。此外，已经表明，将弹性模量与裂纹密度相关的标准模型能够解释在冷喷涂涂层的情况下在涂覆和热处理条件下观察到的模量。
It is well established that cold spray coatings exhibit substantially lower elastic modulus as compared to bulk material of the same composition. It has also been observed that the heat treatment of the cold spray coatings results in a significant increase in the elastic modulus of the coating. To check whether the presence of inter-splat cracks is responsible for the above behavior, a wide variety of metallic materials (Cu, Ag, Zn, Nb, Ta, Ti, and 316L stainless steels) in the powder form have been deposited on a mild steel substrate using the cold spray technique. These coatings in both as-coated and heat-treated conditions have been characterized for their porosity, extent of inter-splat boundary cracking, hardness, and elastic modulus. Results indicate that the elastic modulus of the coatings are substantially lower than the bulk value and also that the heat treatment of the coatings consistently increase their elastic modulus values. It has been shown that the reduction in elastic modulus of cold spray coatings can be related to the extent of inter-splat boundary cracking. Further, it has been shown that the standard models relating elastic modulus to the crack density are capable of explaining the observed modulus in the case of cold spray coatings in the as-coated and heat-treated conditions.