镍基合金C276的高温蠕变性能和行为

Creep Behaviors of Ni-based Alloy C276 at High Temperature

材料问题尤其是燃料包壳材料是超临界水堆的两大难题之一。文中以包壳候选材料之一镍基合金C276为研究对象，对其在600-750℃／130-500MPa条件下进行高温蠕变试验，考察温度和应力对蠕变过程的影响；分析稳态蠕变速率随应力和蠕变断裂时间的变化规律；揭示了蠕变断裂时问与应力间的关系；并比较了分别由Monkman-Grant经验公式和L．M参数法预测各温度的蠕变寿命的可靠性。结果表明：C276具有良好的高温蠕变性能，且600℃低应力水平及650-750℃下的稳态蠕变速率与所施加的应力在双对数坐标系下呈较好的线性关系，但在600℃高应力水平下偏离了这种线性关系。

One of the two challenges about supercritical water reactor is material, especially for the fuel cladding. High temperature creep tests of Nibased alloy C276, one of the candidate materials for the fuel cladding, were carried out at 600-750℃, with stress 130-500MPa. The effects of temperature and stress on creep were investigated, the change laws of the steady state creep rate with stress and time to rupture were analysed, the relations between time to rupture and stress were revealed, and the rupture reliability predicted by Monkman Grant formula and L-M method respectively was compared. The results show that C276 has prominent creep property and a consistent linear relationship between the steady state creep rate and the applied stress in the logarithm coordinate system at 600 ℃ with low stress and 650-750 ℃, but deviating the linear relationship at 600℃ with high stress.