【摘要】 研究了铸造镍基高温合金K44在850—900℃,225—380MPa的高温拉伸蠕变行为.结果表明,实验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时,可以由关系式ε=ε_min（1+c′Δε）exp（n′Δε）来描述.蠕变断裂数据遵守Monkman-Grant规律,裂纹起源于晶界或枝晶界的空洞.更多还原

【Abstract】 High temperature tensile creep behaviors of cast nickel--based superalloy K44 in thetemperature range of 850--900℃ and under the applied stress range of 225--380 MPa have beenstudied. The results indicate that all of the creep curves of test alloys have similar shape: a shortprimary creep and a dominant accelerated creep stage, and the long accelerated stage is due to theinteraction between rafting γ’ particles and dislocations. As the creep strain is a softening stage, theaccelerated creep can be approximately described by expression ε= ε_min（1 + c’△ε）exp（n’△ε）. Thecreep fracture data follow the Monkman--Grant relationship. Cracks originate from the cavities atgrain boundary or interdendritic.更多还原