【摘要】 在高温镍基变形合金中,加入微量Mg元素,可使晶界中的连续条状碳化物变成不连续的块状,从而提高了蠕变应力指数n;并降低晶界扩散系数,提高其蠕变激活能;使晶界能和碳化物-基体的相界能降低,提高了界面结合力。这些因素抑制了晶界滑动,阻止了裂纹的产生和扩展,显著地改善了合金的蠕变性能和持久寿命。更多还原

【Abstract】 The effect of addition of Mg on the creep behaviour of Ni-base wrought superalloy has been investigated. It was found that the trace Mg added may cause the alteration of continueous lath carbide into discontinueous massive one at the grain boundaries. It may also promote the spheroidization of the grain boundary carbide, decrease the diffusion coefficient of grain boundary and increase the activation energy for creep. The grain boundary energy and the boundary energy between grain boundary carbide and matrix are decreased and bonding strength of interface increased. Thus, the creep property and the creep-rupture life as well as the stress exponent of creep of the superalloy may be significantly improved by the impediment of the boundary sliding and the prevention of the nucleation and propagation of cracks.更多还原