Optimization of Laser Deposited Ni-Based Single Crystal Superalloys Microstructure
Optimization of Laser Deposited Ni-Based Single Crystal Superalloys Microstructure
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DOI：
10.4028/www.scientific.net/amr.154-155.1405
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发表时间：
2010-10
期刊：
影响因子：
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通讯作者：
E. Santos;K. Kida;P. Carroll;R. Vilar
中科院分区：
文献类型：
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作者：
E. Santos;K. Kida;P. Carroll;R. Vilar
本文研究了在取向的CMSX-4单晶衬底上激光熔覆Rene N4合金层的组织结构。为了评价激光沉积高温合金高温强度提高的可能性，对不同温度/时间时效循环后的凝固状态下的涂层组织进行了分析。结果表明，只要选择合适的沉积方向和工艺参数，就可以获得单晶的RenéN4镍高温合金镀层。覆层与基材完美结合，不会出现气孔或裂缝。沉积物在衬底上外延生长，因此它们继承了衬底的取向。当激光功率和扫描速度分别在500~800W和4~12 mm/S和(001)晶面上变化时，沉积的材料呈柱状树枝状结构，由亚晶界隔开的相似取向的树枝晶阵列组成，形成单晶。研究了激光熔覆层中有害相的溶解和诱发长方相‘-Ni3Al强化相析出的有效热处理方法。
In this paper, results concerning the microstructure of Rene N4 alloy layers produced by laser cladding on oriented CMSX-4 single crystal substrates are presented. The microstructure of the deposits was analyzed in the solidification condition after different temperature/time ageing cycles in order to assess the possibility of improving high temperature strength of laser deposited superalloys. The present work demonstrates that single crystalline deposits of René N4 nickel superalloy can be obtained provided that the deposition direction and the processing parameters are properly selected. The clad layer is perfectly bonded to the substrate and presents no pores or cracks. The deposits grow epitaxially on the substrate, so they inherit its orientation. For laser beam powers and scanning speeds varying between 500 to 800 W and 4 to 12 mm/s, respectively and (001) substrates, the deposited material presents a columnar dendritic structure consisting of arrays of similarly oriented dendrites, separated by subgrain boundaries, forming a single crystal. Heat treatments effective for the dissolution of detrimental phases and for inducing the precipitation of cuboid ’-Ni3Al strengthening phase precipitates in the laser clads were established.