Ru对一种高W镍基单晶合金蠕变性能的影响

设计并制备了4%W/无Ru、6%W/无Ru以及6%W/2%Ru三种镍基单晶高温合金，通过蠕变性能测试、组织形貌观察、元素分布测定以及XRD谱线测定，研究Ru对一种高W镍基单晶合金蠕变性能的影响。结果表明，提高W含量会促进拓扑密堆相(TCP)析出，从而影响蠕变寿命，6%W/无Ru合金在1070℃/137 MPa条件下的蠕变寿命仅为58 h。元素Ru可改善元素W在γ/γ两相的浓度分布，高温蠕变期间元素Ru可抑制元素W由γ相向γ相扩散。6%W/2%Ru合金经高温蠕变无TCP相析出，其在1070℃/137 MPa条件下的蠕变寿命高达383 h。三种合金在高温蠕变期间，γ相均可形成垂直于应力轴方向的筏状结构，TCP相可破坏筏状结构的连续性，导致γ/γ两相扭折程度加剧，是6%W/无Ru合金蠕变寿命较低的主要原因。

Effect of Ru on Creep Properties of a High Tungsten Containing Ni-based Single Crystal Superalloy

The creep property of 4 nickel-based single crystal superalloys with 4% W, 6% W and 6%W+2%Ru is comparatively studied by creep testing machine, scanning electron microscope, three dimensional atom probe and X-ray diffractometer, aiming to clarify the effect of Ru on the creep performance of the alloy. The results show that the increase in W content will impair the creep performance of the alloy, the creep life of the alloy with 6%W decreases to 58 h at 1070℃/137 MPa. The alloying with Ru can promote the distribution of element W in γ/γ phase more reasonably, whilst inhibit the diffusion of element W from γ phase to γ phase during high temperature creep testing. Therefore, the alloy with 6%W+2%Ru presents a high creep life of 383 h at 1070℃/137 MPa, while no TCP precipitate in the alloy may be observed after high temperature creep testing. During the high temperature creep of the three alloys, the γ phase can form perpendicular to the direction of stress axis, and the TCP phase can destroy the continuity of the raft-like structure, resulting in the increase of the kinking degree of γ/γ phases, which is the main reason for the low creep life of the Ru-free 6%W alloy.