用激光表面熔凝的方法研究激光快冷对改善部件表面状态的作用。结果表明,在激光熔区合金组织发生明显改变,成分均匀,粗大碳化物及共晶组织全部熔化,高温稳定性良好。预先激光处理能抑制σ相析出。已经析出的σ相,激光处理又可使其重熔,这对高温材料的安全使用是很有益的。是一种消除σ相等有害组织的新的技术途径。此外,还分析了快速熔凝的结晶特性及消除σ相的机理。
A cast Ni-base superalloy containing very high contents of Al and Ti (Al+Ti=13.5 wt-％) has been treated by laser rapid melting and solidification. Influence of laserglaze on microstructure and distribution of alloying elements have been studied by TEM, SEM and EMPA. Results showed that the microstructure has changed obviously in the laser treated region, in which alloying elements distributed homogeneously. All the large γ+γ' eutectic, γ'+β peritectic and MC carbides were eliminated. Particularly, microstructure of the laser treated region is excellently thermal stable. Due to extremely high Al+Ti content the σ-phase already existed in cast structure, after aging at 950℃ for 18h, precipitated in enormous quantity. But after laserglaze, no σ-phase was found even aging for 264h. It was evident that if alloy specimen with large quantity of σ-phase was laser treated, not only all the σ-phase particles have been dissolved, but also they could not reprecipitate out even after prolonged aging. Laserglaze can be applied to improve the microstructure and properites of known superalloys, suppressing the precipitation of harmful phases by prior laser surface treatment on machine parts, or eliminating harmful phases present in used parts. It can also be adopted as a powerful means to extend the solid solubility of alloying elements in order to develop new materials.
参考文献
| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] | |
| [8] | |
| [9] | |
| [10] | |
| [11] | |
| [12] |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%