一种含Re单晶镍基合金的组织结构与蠕变性能

通过组织形貌观察及蠕变曲线测定,研究了一种含Re镍基单晶合金在高温的蠕变行为。结果表明,合金经完全热处理后的组织结构是立方γ′相以共格方式嵌镶在γ基体中。在试验的温度和应力范围内,与无Re合金相比较,含Re合金有较好的蠕变抗力及较长的蠕变寿命,并测算出合金在稳态期间的蠕变激活能与应力指数。通过分析位错攀移越过筏状γ′相及影响合金应变速率的因素,研究了合金在稳态蠕变期间的变形机制,其中,元素Re溶入γ基体后可有效阻碍位错运动,降低合金的应变速率,是使合金具有较低应变速率和较长蠕变寿命的主要原因。

Microstructure and Creep Properties of a Single Crystal Nickel-based Superalloy Containing Re

By means of measurement of creep properties and microstructure observation,the creep behaviors of a single crystal nickel-based superalloy containing 4.2%Re were investigated.Results show that after fully heat treated,the microstructure of the alloy consists of the cubical γ phase embedded in the γ matrix as coherent form.In the range of the applied stresses and test temperatures,compared to the free-Re superalloy,the superalloy with 4.2% Re possesses a better creep resistance and longer creep lifetime,and the creep activation energy and stress exponent of the alloy during steady state creep have been calculated.By means of analyzing the dislocation climbing over the rafted γ phase and the factors effecting on strain rates of the alloy,the deformation mechanism of the alloy during steady state creep was investigated.Thereinto,dissolving of Re into the alloy matrix may hinder the dislocations movement and reduce the strain rate of the alloy,which is thought to be the main reason for the alloy possessing lower strain rate and longer creep lifetime.