Numerical and physical simulation of rapid microstructural evolution of gas atomised Ni superalloy powders

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• 作者：Liang Zheng^a ; ^b ; T.L. Lee^c ; ^d ; Na Liu^a ; ^b ; Zhou Li^a ; ^b ; Guoqing Zhang^a ; J. Mi^d ; ^{j.mi@hull.ac.uk} ; P.S. Grant^e
• 关键词：Ni superalloys ; Rapid heating and cooling ; Powder consolidation ; Electron microscopy ; Gleeble thermomechanical simulator ; Finite element modelling
• 刊名：Materials & Design
• 出版年：2017
• 出版时间：5 March 2017
• 年：2017
• 卷：117
• 期：Complete
• 页码：157-167
• 全文大小：3195 K
• 卷排序：117

文摘

Rapid microstructural changes of Ni powders were studied by physical and numerical simulations, and electron microscopy. γ' solvus temperature and incipient melting temperature were critical in controlling the microstructures of the Ni powders. Dendritic structures retained near γ' solvus temperature, but coarsened dramatically near incipient melting temperature. Powders melted and agglomerated near 50% liquid, re-solidified with coarser dendritic structures and micro-segregation. The findings provide general guidance for the temperature limits and time for retaining the fine microstructure of powders.