保載時間對GH220合金周期持久斷裂行為的影響
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載時間下GH220合金周期持久斷裂行為。采用了二種熱處理工藝（等溫彎晶工藝和標準直晶工藝）。結果表明,在750,800,850及900℃,保載時間為0—32min及∞持久條件下,二種晶界狀態的GH220含金都不符合線性累積損傷規則sum（Δt/tr）+Ni/Nf=1。一般表現為明顯地強化。實驗表明,保載時間對GH220合金的周期持久斷裂壽命有很大影響。隨著保載時間的變化,斷裂壽命出現一個最大值。當保載時間小于3min時有弱化的趨勢。本文通過TEM,SEM及金相等手段,研究分析了保載時間嚴重影響GH220合金斷裂壽命的微觀機制并從位錯組態、位錯結構及滯彈性等角度解釋保載時間影響GH220合金不同的周期持久強化程度。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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