保载时间对GH220合金周期持久断裂行为的影响
Influence of Hold Time on the Behaviour of Cyclic Endurance Failure in A Ni-Base Alloy
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摘要: 本文研究了在不同保载时间下GH220合金周期持久断裂行为。采用了二种热处理工艺（等温弯晶工艺和标准直晶工艺）。结果表明,在750,800,850及900℃,保载时间为0—32min及∞持久条件下,二种晶界状态的GH220含金都不符合线性累积损伤规则sum（Δt/tr）+Ni/Nf=1。一般表现为明显地强化。实验表明,保载时间对GH220合金的周期持久断裂寿命有很大影响。随着保载时间的变化,断裂寿命出现一个最大值。当保载时间小于3min时有弱化的趋势。本文通过TEM,SEM及金相等手段,研究分析了保载时间严重影响GH220合金断裂寿命的微观机制并从位错组态、位错结构及滞弹性等角度解释保载时间影响GH220合金不同的周期持久强化程度。Abstract: The behaviour of cyclic endurance failure have been researched under different conditions of temperature and hold time. Two kinds of heat treatment method are used to get the different structure of grain boundary. The results show that the alloy with both kinds of G.B. state are all not agreement with Linear - Damage Summation, t/tr +Nj/Nf = 1 under conditions of temperatuers 750, 800, 850, and 900℃, and hold time 0-32（min）. In general, all specimens are strengthened very clearly. There is great influence of hold time on the cyclic failure life of alloy. The peak of this life vs hold time is occurred. Trend of weakening is begun when hold time is shorter than 3 min.The micro - mechanism have been analyzed by means of TEM, SEM and "so" on. These phenomenon are explained with dislocation structures and anela-sticity.
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