摘要：镍基单晶高温合金具有优异的高温性能和机械性能，由于其耐高温，耐腐蚀，强度高、塑性好等特性，因而广泛应用做航空航天设备发动机的涡轮叶片和导向叶片，本文主要研究DD6单晶镍基高温合金的晶体生长过程，通过DSC测试确定热处理时效方案，对时效后的样品进行硬度测试并分析规律这三方面的分析比较。研究表明，镍基高温合金通过坩埚下降法生长成单晶，消除了晶界，从而提高材料的力学性能，实验表明，温度越高时效时间越长，γ'相粗化程度越大，该单晶材料的硬度越小，同时对材料横截面枝晶间和枝晶干硬度做了测试，结果显示，由于部分枝晶间γ'相形成元素的偏析，导致枝晶间的硬度高于枝晶干的硬度。48703

毕业论文关键词：镍基单晶高温；DD6；晶体生长；热处理；硬度

Growth and mechanical properties of Ni based superalloy single crystal

Abstract：Nickel base single crystal superalloy has excellent high temperature performance and mechanical performance, due to its high temperature resistance, corrosion resistance, high strength, good plasticity characteristics. Therefore, it is widely used for aerospace equipment engine turbine blades and vanes, this paper aims to of DD6 single crystal nickel base high temperature alloy crystal growth process, through the DSC test to determine thermal aging treatment scheme, hardness testing and analysis of the law the three aspects of analyzing and comparing samples after aging. Studies have shown that the nickel base superalloy by crucible descent method growth single crystal, removal of grain boundary, so as to improve the mechanical properties of materials. Experimental results show that the higher the temperature, the longer the aging time, the greater the γ' coarsening extent, the smaller the hardness of the single crystal material while the material between the cross-sectional dendrite and dendrite hardness do the test, the results show that, due section between dendrites γ' phase segregation forming elements, resulting in hardness between the dendrite dendrite higher hardness.

Keywords: Ni based single crystal high temperature; DD6; crystal growth; heat treatment; hardness.

 目录

1 文献综述 3

1.1高温合金概述 3

1.2高温合金的发展 4

1.3镍基单晶高温合金 4

1.3.1成分特征 6

1.3.2组织特征 6

1.3.3性能特征 7

1.4镍基单晶高温合金的用途 7

1.5镍基高温合金单晶生长与性能 8

1.6选题的意义和目的 9

2 实验 10

2.1 晶体生长 10

2.1.1 坩埚下降法（布里奇曼-斯托克巴杰技术） 10

2.1.2 试样制备过程 11

2.2 金相组织观察 11

2.3 DSC测试以及短期时效实验 12

2.4 试样硬度测试 14

3 实验结果与讨论 15

3.1 微观形貌 15

3.1.1 横纵截面微观形貌 15

3.2 热处理工艺制定 17

3.3 短期时效实验 20