CAJ | 학술논문

通过组织形貌观察及蠕变曲线测定,研究了一种含Re镍基单晶合金的高温蠕变行为.结果表明:含4.2％Re单晶合金在1 060-1 100℃温度区间具有较好的承温能力,但表现出较强的施加应力敏感性.经高温蠕变断裂后,在试样不同区域γ′相具有不同的组织形貌,在远离断口区域γ′相形成的筏状组织与施加应力轴方向垂直,而在近断口区域,筏状γ′相的粗化及扭曲程度的增大为该区域发生较大塑性变形所致.在蠕变后期,合金的变形机制是迹线方向为[011]和[011]的滑移位错切入筏状γ′相,主、次滑移系交替开动,使筏状γ′相发生扭折形成不规则的扭曲形态,直至发生断裂是合金的蠕变断裂机制.
통과조직형모관찰급연변곡선측정,연구료일충함Re얼기단정합금적고온연변행위.결과표명:함4.2％Re단정합금재1 060-1 100℃온도구간구유교호적승온능력,단표현출교강적시가응력민감성.경고온연변단렬후,재시양불동구역γ′상구유불동적조직형모,재원리단구구역γ′상형성적벌상조직여시가응력축방향수직,이재근단구구역,벌상γ′상적조화급뉴곡정도적증대위해구역발생교대소성변형소치.재연변후기,합금적변형궤제시적선방향위[011]화[011]적활이위착절입벌상γ′상,주、차활이계교체개동,사벌상γ′상발생뉴절형성불규칙적뉴곡형태,직지발생단렬시합금적연변단렬궤제.
By means of microstructure observation and measurement of creep properties,the high temperature creep behaviors of a single crystal nickel-based superalloy containing Re were investigated.Results show that the single crystal nickel-based superalloy containing 4.2％ Re possesses a better creep resistance at high temperature.After being crept up to fracture,the various morphologies are displayed in the different areas of the sample,and the γ′ phase is transformed into the rafted structure along the direction vertical to the applied stress axis in the regions far from the fracture.But the coarsening and twisting extents of the rafted γ′ phase increase in the regions near the fracture,which is attributed to the occurrence of the larger plastic deformation.In the later stage of creep,the deformation mechanism of the alloy is that the dislocations with [011]and [011]trace features shear into the rafted γ′ phase.The main/secondary slipping dislocations are alternately activated to twist the rafted γ′ phase up to the occurrence of creep fracture,which is thought to be the fracture mechanism of the alloy during creep.