GH690合金的氢致脆性行为研究-《郑州大学学报(工学版)》

文章信息/Info

作者:: 王富强; 王磊; 刘杨; 等.; 东北大学,材料各向异性与织构教育部重点实验室,辽宁,沈阳110004, 东北大学,材料各向异性与织构教育部重点实验室,辽宁,沈阳110004, 东北大学,材料各向异性与织构教育部重点实验室,辽宁,沈阳110004, 东北大学,材料各向异性与织构教育部重点实验室,辽宁,沈阳110004, 东北大学,材料各向异性与织构教育部重点实验室,辽宁,沈阳110004

Author(s):: WANG Fuqiang; WANG Lei; LIU Yang; etc; 1．Key Laboratory of Ministry of Education for Anisotropy and Texture of Materials，Northeastern University，Shenyang 110004，China；2．Angang Steel Company Limited，Anshan，1 14002，China

摘要:: 采用高温高压气相热充氢方法,将氢导入GH690镍基高温合金,其浓度达38.1 mg/kg.对未充氢和充氢试样以相同的应变速率进行室温拉伸试验,通过比较两种条件下GH690合金的拉伸变形行为,考察氢对GH690合金脆化行为的影响.结果表明,氢对GH690合金的屈服强度没有明显的影响,但充氢试样的屈服台阶消失,而且合金的抗拉强度和断裂延伸率明显降低.断口分析发现未充氢试样以延性韧窝断裂为主要特征,而充氢试样则表现出脆性沿晶断裂.GH690合金在拉伸变形时,氢易以Cottrell气团的形式跟随可动位错迁移至晶界,随着塑性变形的进行,位错在晶界处积聚,导致氢富集于晶界.晶界处氢的富集降低了合金的晶界结合强度,使得微裂纹易在晶界处萌生,导致沿晶断裂的发生.

Abstract:: The high-temperature and high-pressure gas-phase thermal hydrogen charging method was used to introduce hydrogen into GH690 nickel-based superalloy with a concentration of 38.1 mg/kg. The results show that hydrogen has no obvious effect on the yield strength of GH690 alloy, but the yield step of the hydrogen-filled sample disappears, and the tensile strength and elongation at break of the alloy are significantly reduced. Fracture analysis showed that the unhydrogenated samples were mainly characterized by ductility ligament fracture, while the hydrogen-filled samples showed brittle along the crystal fracture. When GH690 alloy is tensile deformed, hydrogen easily migrates to the grain boundary with the movable dislocation in the form of Cottrell air mass, and with the plastic deformation, the dislocation accumulates at the grain boundary, resulting in hydrogen enrichment at the grain boundary. The enrichment of hydrogen at the grain boundary reduces the grain boundary bonding strength of the alloy, so that microcracks are easy to germinate at the grain boundary, resulting in fracture along the grain.