本文選題：鋁基原位復(fù)合材料 + 深冷時效循環(huán)處理　； 參考：《中國有色金屬學(xué)報》2015年05期

【摘要】：采用熔體直接反應(yīng)法,以工業(yè)7055鋁合金為基體,利用K2TiF6和K2ZrF6多組元制備Al3(Ti0.5Zr0.5)原位顆粒強(qiáng)化鋁基復(fù)合材料,再將復(fù)合材料經(jīng)過擠壓、固溶時效處理后進(jìn)行深冷時效循環(huán)處理。采用正交實(shí)驗設(shè)計法研究降溫速度、處理時間和循環(huán)次數(shù)對復(fù)合材料顯微組織和力學(xué)性能的影響。采用差示熱分析儀對復(fù)合材料進(jìn)行低溫?zé)岱治?采用SEM和TEM對材料顯微組織進(jìn)行觀察。結(jié)果表明:材料從液氮溫度77 K升溫至165 K左右時出現(xiàn)了明顯的放熱峰,此溫度處出現(xiàn)了相變。熱計算結(jié)果表明該溫度下大量析出了S相(Al2CuMg)。深冷處理后復(fù)合材料內(nèi)部細(xì)小析出相數(shù)量增多,主要組分是η(MgZn2)相和η′(MgZn2′)相;隨著降溫速度、處理時間和循環(huán)次數(shù)增加,性質(zhì)不穩(wěn)定且硬度高的η′相數(shù)量減少,性質(zhì)穩(wěn)定硬度較低的η相數(shù)量增加。與未冷處理試樣相比,深冷時效循環(huán)處理后試樣的平均抗拉強(qiáng)度提高14.7%,沖擊韌性提高10.9%,伸長率提高50%,斷裂機(jī)制為韌窩型斷裂機(jī)制。當(dāng)試樣具有高強(qiáng)度、高韌性時,對應(yīng)的最優(yōu)冷處理參數(shù)為:降溫速度v為1℃/min、保溫時間t為24 h、循環(huán)次數(shù)N為1或2。當(dāng)試樣的伸長率最高時,對應(yīng)的參數(shù)為:v為10℃/min、t為36 h、N為1。復(fù)合材料強(qiáng)化機(jī)制為析出相強(qiáng)化、位錯強(qiáng)化和細(xì)晶強(qiáng)化等。
[Abstract]:Al3Ti0.5Zr0.5Al matrix composites were prepared by melt direct reaction method using industrial 7055 aluminum alloy as matrix and K2TiF6 and K2ZrF6 multicomponent. After extrusion and solution aging, the composites were treated by cryogenic aging cycle treatment.The effects of cooling rate, treatment time and cycle times on the microstructure and mechanical properties of composites were studied by orthogonal experimental design.The low temperature thermal analysis of the composite was carried out by differential thermal analyzer, and the microstructure of the composite was observed by SEM and TEM.The results show that there is an obvious exothermic peak when the temperature of liquid nitrogen rises from 77 K to 165 K, and the phase transition occurs at this temperature.The thermal calculation results show that a large amount of S phase Al _ 2Cu _ (2) MgO is precipitated at this temperature.After cryogenic treatment, the number of fine precipitated phases in the composites increased, the main components were 畏 -mg-Zn2) and 畏 _ (+) MgZn2) phases, and the number of 畏 'phases with unstable properties and high hardness decreased with the increase of the cooling rate, the treatment time and the cycle times.The number of 畏 phase with low hardness is increased.Compared with untreated specimens, the average tensile strength, impact toughness, elongation and elongation of the specimens after cryogenic aging cycle treatment were increased by 14.7%, 10.9% and 50% respectively. The fracture mechanism was dimple fracture mechanism.When the sample has high strength and toughness, the optimal cooling parameters are as follows: cooling rate v = 1 鈩，

本文編號：1744616