7050--T7452鍛件模擬高溫服役環(huán)境下組織性能的演化Evolution of microstructure and properties of 7050-T7452 alloy forging simulation in high temperature service environment

通過拉伸試驗和微觀組織觀察等方法對經(jīng)過不同溫度和時間模擬高溫服役環(huán)境熱暴露處理后7050-T7452
鍛件的室溫拉伸性能以及合金金相組織、析出相的變化情況進(jìn)行系統(tǒng)研究。結(jié)果表明：7050-T7452鍛件在 100~175 ℃下熱暴露處理后，合金的強(qiáng)度隨熱暴露溫度的提高和時間的延長而降低，伸長率隨之增加；當(dāng)熱暴露溫度超過125 ℃后，變化更為明顯；隨熱暴露溫度和時間的變化，合金的晶粒尺寸以及再結(jié)晶程度沒有明顯改變；當(dāng)熱暴露溫度≤125 ℃時，合金晶粒內(nèi)部析出相的尺寸和種類沒有明顯變化；隨熱暴露時間的增加，晶界無析出帶的寬度略有增寬；當(dāng)熱暴露溫度超過 125 ℃時，合金晶內(nèi)的析出相隨溫度以及熱暴露時間的增加而迅速粗化，η相的體積分?jǐn)?shù)增加，晶界無析出帶加寬，合金的強(qiáng)度明顯下降。

The evolution of microstructure and properties of 7050-T7452 alloy forging simulation in high temperature
service environment for different times and temperatures was studied by tensile test and transmission electron microscopy．The results show that the strength of 7050-T7452 alloy forging decreases with the thermal exposed time and temperature increasing in the range of 100?175 ℃, however, the elongation increases. The change of strength is obvious when the exposed temperature is higher than 125 ℃, and the change of grain size and recrystallization is not obvious. When the exposed temperature is lower than 125 ℃, the sizes and species of precipitates do not change obviously. The width of precipitatefree zones (PFZs) increases a little with the exposed time increasing. When the exposed temperature is higher than 125 ℃, the precipitates in matrix are coarser with the exposed temperature and time increasing. Meanwhile, the precipitate size and width of PFZs increase obviously, and the dominant precipitate is η phase. The strength of alloy decreases visibly in this period.

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