一种镍基高温合金熔敷金属的组织及性能

Microstructure and properties of a nickel-base superalloy deposited metal

通过热力学计算、光学显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)等分析了一种镍基高温合金熔敷金属的组织结构和力学性能.结果表明,试验用镍基高温合金熔敷金属的组织主要由柱状NiCr奥氏体以及在其亚晶间分布的少量γ'相、MC型碳化物和Laves相组成.熔敷金属组织结构完好,无裂纹、孔洞等缺陷,但多数合金元素存在偏析行为,其中元素Fe在亚晶粒中心含量较高,元素Mo,Nb,Al和Si在亚晶间含量较高,而元素Cr不存在偏析行为.熔敷金属具有良好的强度和韧性,在拉伸试验及冲击试验中其断裂形式均为塑性断裂,断口形貌为典型的韧窝状.

The microstructure and mechanical properties of a nickel-base superalloy deposited metal were studied by means of thermodynamic calculation,optical microscopy( OM),scanning electron microscopy( SEM) and transmission electron microscopy( TEM). The results indicate that the nickel-base superalloy deposited metal in test was composed of columnar-like NiCr austenitic. There were a few phase,MC carbides and Laves phase in the intergranular of deposited metal. And most of alloying elements in the deposited metal segregated,especially,Mo,Al,Si and Nb were rejected in the intergranular liquid upon solidification,Fe concentrated in grain cores. However,Cr did not apparently segregate. The deposited metal with no cracks,holes and other defects had high strength and good toughness,and its fracture pattern in tensile and impact test was plastic with dimple fracture morphology.