摘要
根据差热曲线分析制定出合金的热处理工艺,结合蠕变性能测试及组织形貌观察,研究了固溶温度对一种高W镍基单晶合金蠕变性能的影响。结果表明:铸态合金中存在明显的枝晶成分偏析,其中元素Al、Ta、W富集于枝晶干,元素Mo、Cr、Co等富集于枝晶间。采用不同温度固溶处理,合金具有不同的蠕变寿命。当固溶温度提高到1 325℃时,可使合金成分的均匀化程度提高,难溶元素得到充分扩散,可降低合金中枝晶干/间的成分偏析,并显著提高合金的蠕变抗力。与1 310℃固溶处理相比,合金经1 325℃高温固溶处理后,在1 072℃、137 MPa条件下的蠕变寿命由35 h提高到48 h。
Heat treatment technique of the single crystal nickel-based superalloy was determined according to the analysis of the differential thermal curve. Through measurement of creep curves and microstructure observation, the influence of the solution temperatures on the creep properties of the superalloy was investigated. Results showed that an obvious segregation of alloying elements occurred in the as-cast nickel-based superalloy, thereinto, the dendrite area was rich in AI, Ta and W, and the interdendritic area was rich Mo, Cr and Co. The superalloy displayed various rupture lifetimes when using the different solution temperatures. As the solution temperature increased to 1 325 ℃, the diffusion of the refractory element W in the alloy was promoted, which decreased the micro segregation of the element in the dendrite/interdendritic areas and improved the creep resistance of the alloy. Compared with solution treatment at 1 310 ℃, after solution treated at 1 325 ℃, the creep rupture lifetime of the superalloy is obviously enhanced to 48 h from 35 h under the applied stress of 137 MPa at 1 072 ℃.
出处
《铸造》
CAS
CSCD
北大核心
2008年第6期549-552,556,共5页
Foundry
基金
国家自然科学基金资助项目(50571070)
关键词
镍基单晶合金
固溶处理
元素偏析
蠕变性能
nickel-based single crystal superalloy
solution treatment
element segregation
creep properties
