Creep anisotropy behavior,deformation mechanism,and its efficient suppression method in Inconel 625 superalloy  

作　　者：Xudong Liu Jiangkun Fan Kai Cao Fulong Chen Ruihao Yuan Degui Liu Bin Tang Hongchao Kou Jinshan Li 

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China [2]Innovation Center,NPU·Chongqing,Chongqing 401135,China [3]AVIC Manufacturing Technology Institute,Beijing 100024,China

出　　处：《Journal of Materials Science & Technology》2023年第2期58-76,共19页材料科学技术（英文版）

基　　金：supported by the National Science and Technology Major Project(Nos.J2019-VI-0023-0140 and MJ-2018-G-48).

摘　　要：Mill products,such as sheets,usually show obvious anisotropy in their mechanical properties,which greatly affects both their applications and workability.In this study,the orientation-dependent tensile and creep behaviors of Inconel 625 alloy sheets with weak local textures were systematically investigated at 650°C.The results showed that Inconel 625 superalloy exhibits nearly isotropic tensile properties;how-ever,obvious creep anisotropy appears when loading along different directions.Creep life in the rolling direction(150±5 h)was approximately 4.5 times longer than in the transverse direction(33±1 h).Se-vere creep anisotropy was found to be determined by two aspects:(i)the change in deformation mecha-nisms along the rolling direction(a combination of boundary sliding,dislocation slipping,and twinning)and the transverse direction(dislocation slipping).Stronger impingement of slip bands on grain bound-aries accelerated intergranular crack initiation and propagation during loading along the transverse direc-tion,which resulted in a short creep life.(ii)The differences in strain compatibility at grain boundaries(i.e.,creep loading along the transverse direction resulted in the initial grains forming strong Brass,Cu,and S textures).Creep cracks preferentially nucleated at the junctions between Cu/Brass texture grains,as these interfaces exhibit the worst strain compatibility(Luster-Morris parameter m≤0.22).Furthermore,pre-stress aging(PSA)treatment is proposed as an efficient method to suppress creep anisotropy.The discrepancy rate of creep life was found to be reduced by nearly 50%after PSA treatment.

关 键 词：Nickel superalloys Creep anisotropy Deformation mechanisms Texture Pre-stress aging 

分 类 号：TB332[一般工业技术—材料科学与工程]