摘要
研究了脉冲电流/温度/应力多场耦合作用下,镍基GH4169合金的变形行为与强韧化机理。结果表明,GH4169合金在脉冲电流/温度/应力作用下,GH4169合金变形抗力降低、塑性变形能力提高,在高温下脉冲电流的引入加剧了原子热振动、金属晶格Pereils力下降,由此降低了合金变形抗力,增强了合金塑性变形协调能力。而当GH4169合金经脉冲电流/温度场耦合时效处理,则可以显著提高合金的高温强度和韧性,脉冲电流/温度耦合作用提高了合金基体空位缺陷密度,促进了其在随后高温变形过程中析出大量数纳米级新γ"相强化相,而脉冲电流/温度场耦合时效处理过程中析出、粗化的γ"相以及其与合金高温变形中新析出数纳米级γ"相的协同作用,使合金实现了强韧化。
The superalloy is one of key metal materials, representing the level of scientific and technological development. Nickel-based superalloy is the most important which has been widely used for rotating component of aerospace. Nickel-based GH4169 alloy shows excellent combination properties including good fatigue property, excellent oxidation and corrosion resistance, as well as the microstructure stability during long-term ageing. The using amount of GH4169 alloy is about 45% of total wrought superalloys. For satisfying high performance of aero-engine, both strength and ductility of GH4169 alloy at high temperature are required to be simultaneously improved for safety servicing. It is an effective method to strengthen alloys by adding alloying elements. The alloying element addition ratio of GH4169 alloy is more than 40%, which unavoidably leads to hard deforming and plasticity declining, so that it restricts the further application of the alloy. Therefore, it is key to find methods realizing strengthening-toughening and without any losing of hot-deforming ability. In this work, the plastic deformation behavior and strengthening- toughening mechanisms of GH4169 alloy with multi-field coupling (electric-pulse current (EPC)/temperature/ stress) were investigated. The results show that the deformation resistance of GH4169 alloy decreases and plastic deformation ability increases with multi-field coupling. The thermal vibration of atoms enhances and thus leads to decreasing of Peierls force with multi-field coupling, which is the essential factor on decreasing of deformation resistance and increasing of plastic deformation coordinate ability. When the alloy aged with electric-pulse treatment (EPT)/temperature coupling, the ultimate strength, yield strength and fracture elongation increase simultaneously at elevated temperatures. The vacancy concentration increases of the alloy aged with EPT/temperature coupling. Vacancy induces ultrafine nm-sized phase to precipitate during tensile deformation at high temperature, which is the key factor on strength and ductility improvement. At the same time, because of the EPT/temperature coupling ageing, part of γ″ phases precipitate around dislocation, while, due to the increasing of γ″ phase size, the ductility of the alloy will be improved. With the multi-field coupling treatment, the strengthening-toughening of GH4169 alloy can be realized depended on an appropriate distribution of two kind sizes of γ″ phase.
作者
王磊
安金岚
刘杨
宋秀
WANG Lei;AN Jinlan;LIU Yang;SONG Xiu(Key Laboratory for Anisotropy and Texture of Materials. Ministry of Education. Northeastern University,Shenyang 110819, China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第9期1185-1194,共10页
Acta Metallurgica Sinica
基金
国家自然科学基金项目Nos.U1708253和51571052
沈阳航空航天大学校引进人才科研启动基金项目No.18YB55~~
关键词
GH4169合金
多场耦合
塑性变形
强韧化
GH4169 alloy
multi-field coupling
plastic deformation
strengthening-toughening
