第三代镍基单晶高温合金DD10长期时效后的微观组织演化  

Microstructure evolution of third generation nickel-based single crystal superalloy DD10 after long-term aging

作　　者：甄兴敏 赵杰[1] 曹铁山[1] ZHEN Xingmin;ZHAO Jie;CAO Tieshan(School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,Liaoning,China)

机构地区：[1]大连理工大学材料科学与工程学院,辽宁大连116024

出　　处：《材料工程》2025年第4期125-133,共9页Journal of Materials Engineering

基　　金：航空发动机及燃气轮机基础科学中心项目(P2021-A-Ⅳ-001-001);船用燃气轮机基础研究项目(MGT2023001);国家自然科学基金项目(51901035)。

摘　　要：对国产第三代镍基单晶高温合金DD10进行了900℃和1050℃的长期时效研究,系统分析了该合金在不同时效条件下的枝晶干与枝晶间微观组织演化差异,以及γ′相和TCP相的尺寸、形态、体积分数等分布特征的演化规律,结果表明:枝晶干和枝晶间的γ′相均产生了粗化,且枝晶干和枝晶间γ′相随时间粗化长大的趋势相同,同一时效温度和时效时间下,枝晶干和枝晶间γ′相形貌稳定因子相近;量化统计结果显示γ′相粗化规律符合LSW模型。1050℃下时效500 h及以后,枝晶干γ′相呈现出了不规则形态,而枝晶内应力的存在使得枝晶间的γ′相形成筏状组织,筏化的方向与一次枝晶的生长方向[001]相一致。在900℃和1050℃时效过程中,枝晶间TCP相析出很少,而枝晶干TCP相体积分数随温度和时间的增加而显著增加;分析TCP相成分后,推测其为μ相;成分平衡相图计算结果显示,实验温度下合金中析出了μ相,TTT曲线计算结果显示,要析出同样体积分数的μ相,900℃下所需的时间比1050℃下要长。难熔元素的偏析使得枝晶干更容易析出TCP相,TCP相的大量析出,使γ′相形态变得不规则,同时使γ′相体积分数下降;长期时效后枝晶干和枝晶间TCP相析出量的差异,最终导致了枝晶干和枝晶间的组织形貌呈现差异。A comprehensive long-term aging study has been conducted on the third-generation nickel-based single-crystal superalloy DD10 at temperatures of 900℃and 1050℃.This investigation systematically analyzes the microstructural evolution disparities between dendrite regions,as well as the evolution of the distribution characteristics of theγ′phase and TCP phase under various aging conditions.The results indicate that during aging at 900℃,theγ′phase undergoes gradual coarsening and growth with increasing aging time.Conversely,at 1050℃,theγ′phase coarsens rapidly and retains a cubic shape after 100 h of aging.The trend ofγ′phase coarsening and growth is consistent between dendrite regions,with minimal difference in the average size of theγ′phase within these regions under the same aging duration.Quantitative statistical analysis reveals that the coarsening of theγ′phase aligns with the Lifshitz-Slyozov-Wagner(LSW)model.Following aging at 1050℃for 500 h or more,theγ′phase within the dendritic core adopts an irregular shape,and stress within the dendrites leads to the formation of a valuated structure in theγ′phase between dendrites,with the valuation direction coinciding with the primary dendrite growth direction[001].During aging at both 900℃and 1050℃,TCP phase precipitation between dendrites is minimal,whereas the TCP phase volume fraction within dendrite stems increases significantly with increasing temperature and time.After aging at 1050℃for 2000 h,the TCP phase volume fraction reaches 8.25%.Compositional analysis suggests that the TCP phase is likely theμphase.Equilibrium phase diagram calculations confirm the precipitation of theμphase in the alloy at the experimental temperatures,and TTT curve calculations indicate that the time required to precipitate the same volume fraction ofμphase is longer at 900℃compared to 1050℃.

关 键 词：单晶高温合金 长期时效 枝晶偏析 γ′相 TCP相 

分 类 号：TG132.32[一般工业技术—材料科学与工程]