摘要
研究了一种新型铸造镍基高温合金K444在850-900℃／225-380MPa的高温拉伸蠕变行为。结果表明：K444合金的显微组织主要由γ′相、γ′／γ′共晶以及碳化物和氮、硼化物组成，热处理试样中γ′粒子有球状和椭圆状两种，γ′粒子在减速阶段末期开始筏形化，之后与位错相互作用；K444合金蠕变曲线具有较短的初始阶段和较长的加速阶段，加速阶段较长是由于筏形化的γ′粒子和位错相互作用促成的，加速蠕变为应变软化阶段，可用关系式ε=εmin（1＋c′△ε）来描述，蠕变断裂数据遵循Monkman-Grant规律，裂纹起源于晶界或枝晶界的空洞。
The high temperature tensile creep behavior of a new type of cast nickel base superalloy K444 under the condition of 850-900℃/225-380MPa MPa was studied. The results show that the microstructure of K444 alloy was mainly composed of γ′phase, γ′/γ′eutectic, carbides, nitrogen and boride. γ′ phase in heat treated sample had spherical and elliptical two forms. The γ′ particles started rafting in the end of deceleration period, and then interacted with the dislocation. Creep curves of K444 alloy had shorter initial stage and long acceleration stage, which resulted by the rafting of γ′ particles and the interaction of the dislocations. The accelerated creep should be strain softening stage, and it can be described by the formula of ε=εmin（1＋c′△ε）. The creep rupture data complied with Monkman-Grant rules, and the void cracks originated from the boundary or branch grain boundary.
出处
《理化检验（物理分册）》
CAS
2013年第8期510-515,共6页
Physical Testing and Chemical Analysis(Part A:Physical Testing)
关键词
镍基高温合金
高温蠕变
蠕变断裂
nickel based superalloy
high temperature creep
creep fracture
