论文部分内容阅读
研究了一种[001]取向镍基单晶合金的蠕变特征和变形期间的微观组织结构.结果表明:在低温高应力和高温低应力条件下,合金具有较长的蠕变寿命和较低的稳态蠕变速率;在700℃,720MPa条件下,透射电镜(TEM)观察显示蠕变期间的变形特征是1/2<110>位错在基体中运动,发生反应形成1/3<112>超肖克利(Shockley)不全位错,切入γ′相后产生层错.在900℃,450MPa条件下,没有出现蠕变初始阶段,γ′相从立方体形态演化成筏形;在加速蠕变阶段,多系滑移开动,大量位错剪切γ′相是变形的主要机制.在1070℃,150MPa条件下,γ′相逐渐转变成筏形组织,并在γ/γ′界面处形成致密的六边形位错网,位错网可以阻止位错切入γ′相,提高蠕变抗力;在蠕变后期,位错以位错对形式切入γ′相,是合金变形的主要方式.
The creep characteristics of a [001] oriented nickel-based single crystal alloy and the microstructure during deformation were investigated. The results show that the alloy has a long creep life and a low creep life under low temperature and high stress and high temperature and low stress The steady-state creep rate at 700 ℃ and 720MPa shows that the deformation character during creep is that the deformation of 1/2 <110> moves in the matrix and the reaction forms 1/3 <112 > Shockley is not fully dislocated and a fault occurs when the γ ’phase is cut in. At the initial stage of creep at 900 ° C and 450 MPa, the γ’ phase evolves from cubic to raft shape; at accelerated creep Stage, multi-system slip, a large number of dislocation shear γ ’phase is the main mechanism of deformation in the 1070 ℃, 150MPa conditions, γ’ phase gradually transformed into a raft organization, and in the γ / γ ’interface to form a dense The hexagonal dislocation network can prevent the dislocations from cutting into the γ ’phase and improve the creep resistance. In the later stage of creep, the dislocations cut into the γ’ phase in the form of dislocation, which is the main mode of alloy deformation.