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探讨了镍基单晶合金在承受机械载荷和温度载荷时的寿命预测模型。基于疲劳 -蠕变试验及热机械疲劳 -蠕变试验 ,分析了各影响寿命的主要因素。典型断口的 SEM分析表明 :断口由小剖面组成 ,在小剖面的中心 (附近 )有形核于铸造缺陷的小空穴 ,这些小孔洞有不同程度的长大 ,相对于蠕变 ,疲劳断口的小空穴数量 (密度 )明显增加。详细的观察表明 ,这些空穴对高温带保载的疲劳断口而言 ,承受拉伸保载的断口上的空穴明显较承受压缩保载断口上的空穴大。概括而言 ,镍基单晶合金的破坏受到的影响为空穴扩张和材料消耗 ,对蠕变、疲劳和热疲劳都相同。针对镍基单晶合金叶片的温度、载荷特点 ,可以用线形寿命模型统一描述工作寿命。
The life prediction model of nickel-base single crystal superalloy subjected to mechanical load and temperature load was discussed. Based on the fatigue-creep test and the thermo-mechanical fatigue-creep test, the main factors influencing the life span were analyzed. The SEM analysis of the typical fracture shows that the fracture consists of small sections with small holes nucleating in the casting defects at the center (near) of the small section. These small holes have different degrees of growth. Compared with creep and fatigue fracture The number of holes (density) is significantly increased. Detailed observations show that these cavities have significantly larger holes on the fracture under tensile loading than those under compressive fracture with respect to the fatigue fracture maintained at high temperature. In summary, the destruction of nickel-based single crystal alloys is affected by cavity expansion and material consumption, with the same creep, fatigue and thermal fatigue. For the nickel-based single crystal alloy blade temperature, load characteristics, you can use the linear life model to describe a unified life expectancy.