Effects of Temperature and Pressure of Hot Isostatic Pressing on the Grain Structure of Powder Metallurgy Superalloy

Liming Tan; Guoai He; Feng Liu; Yunping Li; Liang Jiang

doi:10.3390/ma11020328

Effects of Temperature and Pressure of Hot Isostatic Pressing on the Grain Structure of Powder Metallurgy Superalloy

Materials (Basel). 2018 Feb 24;11(2):328. doi: 10.3390/ma11020328.

Authors

Liming Tan^{1

2

3}, Guoai He^{4

5}, Feng Liu^{6

7

8}, Yunping Li^{9

10

11}, Liang Jiang^{12

13

14}

Affiliations

¹ State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China. limingtan@csu.edu.cn.
² Powder Metallurgy Research Institute, Central South University, Changsha 410083, China. limingtan@csu.edu.cn.
³ High Temperature Materials Research Institute, Central South University, Changsha 410083, China. limingtan@csu.edu.cn.
⁴ State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China. heguoai@csu.edu.cn.
⁵ Light Alloy Research Institute, Central South University, Changsha 410083, China. heguoai@csu.edu.cn.
⁶ State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China. liufeng@csu.edu.cn.
⁷ Powder Metallurgy Research Institute, Central South University, Changsha 410083, China. liufeng@csu.edu.cn.
⁸ High Temperature Materials Research Institute, Central South University, Changsha 410083, China. liufeng@csu.edu.cn.
⁹ State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China. lyping@csu.edu.cn.
¹⁰ Powder Metallurgy Research Institute, Central South University, Changsha 410083, China. lyping@csu.edu.cn.
¹¹ High Temperature Materials Research Institute, Central South University, Changsha 410083, China. lyping@csu.edu.cn.
¹² State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China. liang.jiang@csu.edu.cn.
¹³ Powder Metallurgy Research Institute, Central South University, Changsha 410083, China. liang.jiang@csu.edu.cn.
¹⁴ High Temperature Materials Research Institute, Central South University, Changsha 410083, China. liang.jiang@csu.edu.cn.

Abstract

The microstructure with homogeneously distributed grains and less prior particle boundary (PPB) precipitates is always desired for powder metallurgy superalloys after hot isostatic pressing (HIPping). In this work, we studied the effects of HIPping parameters, temperature and pressure on the grain structure in PM superalloy FGH96, by means of scanning electron microscope (SEM), electron backscatter diffraction (EBSD), transmission electron microscope (TEM) and Time-of-flight secondary ion spectrometry (ToF-SIMS). It was found that temperature and pressure played different roles in controlling PPB precipitation and grain structure during HIPping, the tendency of grain coarsening under high temperature could be inhibited by increasing HIPping pressure which facilitates the recrystallization. In general, relatively high temperature and pressure of HIPping were preferred to obtain an as-HIPped superalloy FGH96 with diminished PPB precipitation and homogeneously refined grains.

Keywords: grain structure; hot isostatic pressing; powder metallurgy superalloy; prior particle boundary.