Title定向凝固镍基高温合金的反常屈服和中温脆性行为
Other TitlesAnomalous yield and intermediate temperature brittleness behaviors of directionally solidified nickel-based superalloy
Authors盛立远
杨芳
郭建亭
奚廷斐
Affiliation北京大学 深圳研究院,深圳,518057
深圳宝安国际机场 深圳航空有限责任公司,深圳,518128
中国科学院 金属研究所,沈阳,110016
Keywords镍基高温合金 定向凝固 反常屈服 中温脆性 微观组织 nickel-based superalloy directional solidification anomalous yield intermediate-temperature brittleness microstructure
nickel-based superalloy
directional solidification
anomalous yield
intermediate-temperature brittleness
microstructure
Issue Date2014
Publisher中国有色金属学报英文版
Citation中国有色金属学报(英文版).2014,(3),673-681.
Abstract采用真空冶炼和定向凝固工艺制备一种具有优异抗腐蚀性能的镍基高温合金,并利用光学显微镜、扫描电镜和透射电镜研究合金的微观组织,分析合金在不同温度下的拉伸性能。结果表明,除γ′颗粒和γ基体外,在合金晶界上析出了一些MC碳化物、M3B2硼化物和Ni5Hf相。合金拉伸性能对温度有很强的依赖性,并呈现明显的的反常屈服和中温脆性行为。在650°C以下,合金的屈服强度随着温度的升高而略微降低,但抗拉强度几乎没有变化。当温度在650°C和750°C之间时,合金的屈服、抗拉强度快速升高,但拉伸塑性显著降低,并在700°C时达到最低值。当温度进一步升高时,合金的屈服、抗拉强度逐渐降低,塑性升高。透射电镜观察发现,在低温条件下,位错切割γ′是主要的变形机制;在高温条件下,位错绕过γ′是主要的变形机制;由位错切割γ′转变至位错绕过γ′的温度约为800°C。合金的反常屈服和中温脆性行为主要归因于合金中高的γ′含量。此外,碳化物和共晶组织对合金的中温脆性行为也有影响。
A nickel-based superalloy with good corrosion resistance was fabricated by directional solidification, and its microstructure and tensile properties at elevated temperatures were investigated. Microstructure observations reveal that the gamma' precipitates are arrayed in the gamma matrix regularly with some MC, Ni5Hf and M3B2 particles distributed along the grain boundary. The tensile tests exhibit that the tensile properties depend on temperature significantly and demonstrate obvious anomalous yield and intermediate-temperature brittleness (ITB) behavior. Below 650 degrees C, the yield strength decreases slightly but the ultimate tensile strength almost has no change. When the temperature is between 650 degrees C and 750 degrees C, the yield and ultimate tensile strengths rise rapidly, and after then they both decrease gradually with temperature increasing further. The elongation has its minimum value at about 700 degrees C. The TEM examination exhibits that sharing of the gamma' by dislocation is almost the main deformation mechanism at low temperatures, but the gamma' by-pass dominates the deformation at high temperatures. The transition temperature from shearing to by-pass should be around 800 degrees C. The anomalous yield and intermediate-temperature brittleness behaviors should be attributed to the high content of gamma'. In addition, the carbides and eutectic structure also contribute some to the ITB behaviors of the alloy.
URIhttp://hdl.handle.net/20.500.11897/214690
ISSN1003-6326
DOI10.1016/S1003-6326(14)63110-1
IndexedSCI(E)
EI
中国科技核心期刊(ISTIC)
中国科学引文数据库(CSCD)
Appears in Collections:深圳研究生院待认领

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