Atlas Journal of Materials Science 2018-07-22T17:05:14+00:00 Abdelmajid Kassem Open Journal Systems <p>Atlas Journal of Materials Science is an open access, peer-reviewed international journal that publishes original research articles, short communications, and review articles in all fields of Atlas Journal of Materials Science.</p> Influence of solution treatment on microstructure and stress rupture properties of K439 nickel-base superalloy 2018-07-22T17:05:14+00:00 Jin Xu Mingjun Zhang Xin Tang Guangyu Yang Jingyang Chen Qing Li Chengbo Xiao <p>The isochronal solution treatment (4h) in the 1080-1190°C range with air cooling are performed to investigate the effects of solution temperature on the microstructure and stress rupture properties of K439 alloy. The detailed as-cast and solution treated microstructures were analyzed through optical microscopy (OM), scanning electron microscopy (SEM) and differential scanning calorimeter (DSC). The experimental results show that the as-cast alloy exhibited a typical dendritic structure with five phases of γ, γ´, γ/γ´, η and MC. After solution heat treated at 1080°C, although all of the γ´ particles in the dendritic cores were dissolved, there were still some of these precipitates in the interdendritic regions beside η phase. With the solution temperature increasing to 1150°C, all of the γ´ and η solutioned and a uniform microstructure was observed. Furthermore, increasing the temperature to 1210°C, a small amount of incipient melting occurred in the alloy. The stress rupture life of K439 alloy at 760°C/530MPa increased with the rising of solution temperature and reached to the top value under the solution temperature of 1150°C. The optimum solution treatment considered to be 1150 C/4 h followed by air cooling.</p> 2018-06-24T00:00:00+00:00 ##submission.copyrightStatement##