NiAl合金时效沉淀相微观组织研究
通过 NiAl 合金时效热处理实验和 SEM 组织观察，利用相场方法,使用 Matlab7.0 编程,研究了时效温度，时效时间对 NiAl 合金γ′相沉淀过程的影响规律和γ′相的转变动力学和粗化行为。
随着时效温度的升高,NiAl 合金γ′相的微观形貌由低温时的长方块状分布转变为较高温度时的方块状分布，沉淀平均粒径减小，析出相的数目增多，沉淀达到平衡时γ′相的最终体积分数减小，粗化速率增大。随着时效时间的延长，NiAl 合金γ′相的微观形貌由最初的圆球状转变为方块状或长方块状分布，同时γ′相沉淀形核长大，沉淀体积分数增大。26734
毕业论文关键词 NiAl 合金 γ′沉淀相 相场模拟 时效处理
Title The research of the γ′ precipitates in NiAl alloy
Abstract
NiAl alloy is the ideal next generation of high temperature structure material.
The main strengthening phase of high temperature alloy is γ′ precipitates, during
the aging of nickel based alloy, γ′ orderly precipitate precipitates from the matrix
precipitation. The volume fraction, size, morphology and spatial distribution of
precipitate determines the degree of enhancement of alloy. So, the study on the
microstructure and phase of γ′ prime coarsening behavior is very important to
improve the performance of nickel based superalloy.
By the observation of the aging heat treatment and SEM microstructure of NiAl
alloy, based on Phase-field model, with Matlab7.0 programming, we investigated
the effects of temperature and time on the microstructure evolution and coarsening
behavior of γ′ phase in NiAl alloys.
With the increase of the aging temperature, the γ′ phase morphology changes from
connected rectangle shape to separated cuboidal. Average particle size decreases.
Precipitation balance final volume fraction of gamma prime phase. Coarsening rate
increases. With the increase of aging time, the micro morphology of NiAl phase
alloy γ′ changed from the initial spherical, square shaped or rectangular block
distribution. At the same time, γ′ precipitation nucleation and growth, the
increase of the volume fraction of precipitation.
Keywords NiAl alloy γ′ precipitates Phase-field simulation aging treatment目 次
1 绪论1
1.1 研究背景. 1
1.2 研究方法. 1
1.3 镍基高温合金强化种类. 4
1.4 Ni3Al 的强化作用...4
1.5 本论文研究内容. 5
2 NiAl 合金的时效处理...6
2.1 研究方案. 6
2.2 实验材料及设备. 7
2.3 实验过程. 8
2.4 金相观察... 10
2.5 本章小结... 12
3 相场模拟中的NiAl 合金时效沉淀过程13
3.1 不同时效温度下 NiAl 合金微观结构演变. 13
3.2 时效温度对 NiAl 合金沉淀过程的影响规律. 16
3.3 不同时效时间下 NiAl 合金微观结构演变. 17
3.4 时效时间对 NiAl 合金沉淀过程的影响规律. 18
3.5 本章小结... 20
4 NiAl 合金沉淀相粗化.21
4.1 时效温度对 NiAl 合金粗化行为的影响. 22
4.2 时效时间对 NiAl 合金粗化行为的影响. 23
4.3 本章小结... 24
结论25
致谢26
参考文献271 绪论
1.1 研究背景
镍基高温合金具有非常优秀的高温性能，其工作温度范围为 700-1000℃[1]。因而,镍基高
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