蒋立武李树索邱自成韩雅芳
金属学报
采用螺旋选晶法制备Ni3Al基单晶合金IC6SX试棒, 研究了不同拉晶速率对凝固组织和高温持久性能的影响. 结果表明, Ni3Al基单晶合金IC6SX凝固组织为树枝状, 随着拉晶速率从1.5 mm/min增加到6 mm/min, 一次枝晶间距逐渐减小. 与普通镍基高温合金不同, 位于枝晶干处的次生γ'相尺寸比枝晶间处的大. 随着拉晶速率的增加, 枝晶干和枝晶间处的γ'相尺寸都逐渐减小, 由不规则形状逐渐立方化, 枝晶间处的初生γ'相的数量逐渐增多. 一次枝晶间距和γ'相尺寸对高温持久性能影响显著, 随着拉晶速率的增加, 组织细化, 铸态IC6SX单晶合金的高温持久寿命增加.
关键词:
Ni3Al
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single crystal superalloy
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withdrawal rate
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primary dendrite arm spacing
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stress rupture
刘心刚
,
雷强
,
王莉
,
李相伟
,
钱宝
,
楼琅洪
材料研究学报
通过金相显微镜(OM)、扫描电镜(SEM)和电子探针(EPMA)等手段研究了第三代单晶高温合金DD33在固溶处理过程中组织的演变.结果表明:在第三代单晶高温合金DD33中,枝晶间γ'相在1310℃保温时明显长大,而在1320℃/2 h固溶后完全溶解;(γ+γ')共晶在高于1320℃时显著溶解;MC碳化物在固溶处理过程中发生溶解,由草书体状向颗粒状转变,促进枝晶间y'相的长大;随着固溶温度的提高共晶γ'相中A1、Ta、Cr、Co等元素的偏析加剧,这一现象可能是上坡扩散引起的.
关键词:
金属材料
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单晶高温合金
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固溶处理
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微观组织
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共晶
范志东
,
王栋
,
楼琅洪
材料研究学报
研究了镍基单晶高温合金DD10在760℃和980℃条件下低周疲劳过程中的拉-压不对称性行为,并对其机制进行了深入探讨.结果表明,在疲劳试验初期,当应变幅较低时,在两种温度条件下拉-压不对称性都不明显,且拉力略大于压力;随着循环周次或应变幅的增加合金的拉-压不对称性逐渐明显,在760℃时拉力明显大于压力,而在980℃时拉力却明显小于压力.循环初期的拉-压不对称性行为与基体应力状态有关,而在大应变幅下和循环应力稳定阶段拉-压不对称性的正负属性和程度与位错在不同温度拉伸和压缩过程中克服γ'粒子的运动方式不同有关.
关键词:
金属材料
,
单晶高温合金
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低周疲劳
,
拉压不对称性
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位错形貌
Author X.A. Zhang1)
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H.Q. Xia1)
,
Z.T. Wu1)
,
Y.F. Han1)
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R. Shi2) and G.X. Hu2) \= 1) Mechanical Properties Laboratory
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Beijing Institute of Aeronautical Materials
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Beijing 100095
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China2) The State Education Commission Open Research Laboratory for High Temperature
金属学报(英文版)
Materials and Testing, Shanghai Jiao Tong University, Shanghai 200030, ChinaManuscript received 18 October 1998 The threestage creep behavior of DD3 single crystal superalloy had been studied. The results show that the creeprupture properties of DD3 single crystal satisfy the requirements for high performance turbine blade application. The influence of crystal orientation on the creeprupture property of DD3 single crystal was tested and discussed. An engineering criterion to evaluate the regimes of secondary and tertiary creep is proposed, and this method gives a reasonable result for practical applications. The fractography and TEM micrography of the tested specimens had been studied, and it is determined that the glidecontrolled creep is the basic creep mechanism of DD3 single crystal at intermediate temperature, but the thermally activated processes become dominant at higher temperature.
关键词:
threestage creep curve
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null
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null
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null
