p1=1150，1250，1350 ℃）和二次峰值溫度（Tp2=850，950，1050，1150，1250，1350，1450 ℃）下的焊接熱影響區(qū)（HAZ），研究了峰值溫度和熱循環(huán)次數(shù)對C-HRA-2合金HAZ微觀組織演變的影響，并測試了其顯微硬度。采用光學顯微鏡、掃描電鏡和透射電鏡對HAZ的微觀結(jié)構(gòu)和碳化物進行表征。結(jié)果表明，在Tp1=1150 ℃的HAZ中，可觀察到沿晶界析出的細小的M23C6碳化物。在Tp1>1250 ℃的HAZ中，在晶界附近發(fā)現(xiàn)由于成分液化而導致的γ基體與M23C6碳化物組成的微觀結(jié)構(gòu)。當Tp2在1050~1250 ℃，可在HAZ中的晶界附近觀察到與在Tp1=1150 ℃的HAZ中類似結(jié)構(gòu)的碳化物，這是由Tp1和Tp2間基體中Cr的固溶度差值導致的。在Tp2>1250 ℃的HAZ中，在晶界附近可觀察到與在Tp1=1250 ℃的HAZ中類似的熔融態(tài)微觀組織。隨著Tp2的升高，顯微硬度出現(xiàn)很大程度的起伏，在Tp2=1250 ℃的試樣顯微硬度要稍高于母材硬度，這是因為晶界附近出現(xiàn)的碳化物起到了晶界強化作用。;The welding heat-affected zone (HAZ) of C-HRA-2 nickel-based alloy under various primary peak temperatures (Tp1=1150, 1250, and 1350 °C) and the secondary peak temperatures (Tp2=850, 950, 1050, 1150, 1250, 1350, and 1450 °C) was obtained by welding thermal simulation. The effect of peak temperature (Tp) and thermal cycling times on the evolution of simulated HAZ microstructure of C-HRA-2 alloy was investigated. The microhardness of simulated HAZs was measured. The HAZ microstructure and carbide were characterized by the optical microscope, scanning electron microscope, and transmission electron microscope. Results show that the fine M23C6 carbides appear along the grain boundaries in the simulated HAZ with Tp1=1150 °C. For HAZs with Tp1>1250 °C, the γ matrix bonded with M23C6 carbides appears near the grain boundaries due to component liquefaction. When Tp2 is 1050–1250 °C, the carbides similar to those in HAZ with Tp1=1150 °C can be observed near the grain boundaries due to the difference in the solid solubility of Cr in the matrix obtained at Tp1 and Tp2. In HAZ with Tp2>1250 °C, the melted microstructure similar to that with Tp1=1250 °C can be observed near the grain boundaries. The microhardness fluctuates significantly with increasing the Tp2. The microhardness of specimen with Tp2=1250 °C is slightly higher than that of the base material, because of the grain boundary strengthening effect of the carbides near the grain boundaries."/>
23C6碳化物;C-HRA-2 alloy;welding thermal simulation;microstructure evolution;M 23C6 carbide"/>