镍基单晶高温合金的拉伸断裂行为  

Tensile Fracture Behavior of Ni-based Single Crystal Superalloy

作　　者：武丹[1] 田礼熙[2] 马朝利[2] 史一宁 

机构地区：[1]北京航空材料研究院先进高温结构材料国防科技重点实验室,北京100095 [2]北京航空航天大学材料科学与工程学院,北京100083 [3]空军驻北京地区军事代表室,北京100024

出　　处：《材料导报》2016年第12期76-80,89,共6页Materials Reports

基　　金：国家973项目(2012CB619503)

摘　　要：对[001]、[011]和[111]取向的镍基单晶高温合金的不同取向的弹性模量及硬度做了表征,并分析了[011]和[111]取向的单晶在室温和1070℃的拉伸断口形貌。研究结果表明:合金的弹性模量及拉伸断裂存在各向异性。室温下,[011]取向试样拉伸断裂变形不均匀,断面为椭圆形;[111]取向的试样断裂面为圆形,没有发生颈缩。[011]、[111]取向断口均由裂纹源区、扩展区及瞬断区组成。室温下,合金的拉伸断口为剪切型韧性断裂;高温下,合金的拉伸断口为微孔聚集型韧性断裂。The Young′s moduli and microhardnesses of a kind of Ni-based single crystal superalloy with varied crystal orientations were characterized and tensile characteristics of the alloy specimens with [011]and [111]crystal orientations at ambient temperature and 1070℃ were studied.It can be concluded that crystal orientation has a significant influence on the single crystal nickel-based superalloy′s elastic modulus,as it exhibited obvious tensile anisotropy.At ambient temperature,non-uniform deformation of this alloy by tensile fracture was observed.The fracture surface of[011]oriented specimen presented elliptical shape,while the fracture surface of[111]oriented specimen exhibited circular shape and no necking occured.At room temperature,the different areas of crack nucleation,propagation and final fracture area were clearly observed.The fracture mode was characterized by tearing ridges and dimples mixed at room temperature.At high temperature,the fracture surface presented mixed characteristics of holes and dimples and the fracture was dominated by micro-void coalescence.

关 键 词：镍基单晶高温合金 各向异性 拉伸断裂 形貌 

分 类 号：TG1[金属学及工艺—金属学]