GH4141难变形高温合金铸态组织析出相鉴别及均匀化过程中演变行为

Identification of precipitates in the as-cast microstructure and its evolution behavior during homogenization of a difficult-to-deform GH4141 superalloy

摘要:

GH4141变形高温合金因具有较高的高温强度和良好抗氧化性能，被广泛用于制造航空航天发动机高温承力部件。本文基于化学成分分析及晶体学法，对GH4141难变形高温合金铸态组织中典型析出相进行了详细鉴别与解析。通过高温均匀化实验，分析了均匀化过程中析出相回溶行为。1130~1160 oC中低温均匀化条件下，原铸态组织中针状σ相、板状η相、M3B2型硼化物以及γ’强化相等回溶至基体，M6C型碳化物仍可存在。1190~1210 oC高温均匀化条件下，合金中包括M6C在内的大部分析出相已回溶至γ基体，组织中仅剩余少部分MC型碳化物。MC型碳化物在固液两相区回溶，较难通过均匀化热处理彻底回溶消除。

Abstract:

GH4141 wrought superalloy is widely used in the manufacture of high-temperature load-bearing components for aerospace engines due to its high strength and good oxidation resistance at high temperatures. In this paper, based on chemical composition analysis and crystallographic method, the typical precipitates in the as-cast GH4141 alloy were identified and analyzed in detail. The dissolution behaviors of the precipitates during the homogenization process were analyzed through the high-temperature homogenization experiments. Under the medium and low temperature homogenization conditions of 1130~1160 oC, the needle-like σ phase, plate shape η phase, M3B2 boride and γ’ strengthening phases of the original as-cast structure are dissolved into the matrix, while the M6C carbide can still be existed. Under the condition of high temperature homogenization at 1190~1210 oC, most of the precipitates including M6C in the alloy have been dissolved into the γ matrix, and only a small part of MC carbides remain in the structure. Besides, it’s worth noting that the MC carbides are dissolved in the solid-liquid two-phase region, and the MC carbides are difficult to be completely dissolved and eliminated through homogenization heat treatment.