Corundum-based (Al2O3) refractory materials prepared by powder metallurgy superalloy powder were heat treated at 950-1350 ℃ for 60 min in order to study the effect of temperature on the microstructure and particle shedding of corundum-based refractory materials. The phase structure of the refractory materials before and after heat treatment was analyzed by XRD. Scanning electron microscopy (SEM) with energy dispersive spectrum (EDS) was used to characterize the microstructure and phase composition of the refractory samples. In addition, the adhesion experiment was used to evaluate the particle shedding of the refractory materials after heat treatment at different temperatures, and explore the mechanism of pre-heating treatment reducing the possibility of particle shedding. Thermal shock test was used to evaluate the thermal shock resistance of refractory materials after heat treatment at different temperatures. The apparent porosity and bulk density were measured. The results show that with the increase of preheating temperature, the composition of calcium aluminate cement binder in refractories is gradually changed from CaAl2O4 (CA) to CaAl4O7 (CA2), and the fine ceramic particles in refractories are sintered together until the interconnected network structure is formed. With the increase of preheating temperature, the fine refractory particles in the refractory are gradually wet and spread on the large particles as aggregated and connected to form a network structure, and finally the large particles are coated. The particle adhesion of refractory gradually increases with the increase of heating temperature. The heat treatment has minor effect on the apparent porosity, bulk density and heat shock resistance of the refractory materials. However, with the increase of heating temperature, the local peeling degree of the refractory surface and mass loss rate in the thermal shock test are significantly improved. The particle shedding is obviously reduced whereas preheating for 60 min at 1150-1350 ℃, and the relative suitable preheating temperature is in the range of 1250-1350 ℃.
ZHANG G Q , ZHANG Y W , ZHENG L , et al. Research progress in powder metallurgy superalloys and manufacturing technologies for aero-engine application[J]. Acta Metallurgica Sinica, 2019, 55 (9): 1133- 1144.
ZHAO Y S , ZHANG J , SONG F Y , et al. Effect of trace boron on microstructural evolution and high temperature creep perfor-mance in Re-containing single crystal superalloys[J]. Progress in Natural Science, 2020, 30 (3): 97- 107.
ZOU J W , WANG W X . Development and application of P/M superalloy[J]. Journal of Aeronautical Materials, 2006, 26 (3): 244- 250.
SHENOY M M , KUMAR R S , MCDOWELL D L . Modeling effects of nonmetallic inclusions on LCF in DS nickel-base superalloys[J]. International Journal of Fatigue, 2005, 27 (2): 113- 127.
YANG J L , ZHU X M , XIONG J Y , et al. Effect of inclusion size and distribution on low cycle fatigue properties of an FGH97 superalloy[J]. Rare Metal Materials and Engineering, 2020, 49 (5): 1614- 1622.
FENG Y F , ZHOU X M , ZOU J W , et al. Interface reaction mechanism between SiO2 and matrix and its effect on the deformation behavior of inclusions in powder metallurgy superalloy[J]. Acta Metallurgica Sinica, 2019, 55 (11): 81- 91.
JIN W Z , ZHANG W , LI T J , et al. Electromagnetic purification of master alloy ingot of K417 superalloy in vacuum[J]. Chinese Journal of Vacuum Science and Technology, 2011, 31 (5): 589- 593.
GAO X Y , ZHANG L , QU X H , et al. Effect of interaction of refractories with Ni-based superalloy on inclusions during va-cuum induction melting[J]. International Journal of Minerals, Metallurgy and Materials, 2020, 27 (11): 1151- 1159.