(1. 中南大學(xué) 輕合金研究院，長沙 410083；
2. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 為了研究6082鋁合金鍛件亞結(jié)構(gòu)組織演變對力學(xué)性能的影響，本文在不同應(yīng)變速率下，對6082鋁合金進(jìn)行鍛造試驗(yàn)，通過EBSD和TEM表征，探討不同熱處理?xiàng)l件下鍛件的亞晶體積分?jǐn)?shù)和位錯(cuò)密度對析出強(qiáng)化的影響。結(jié)果表明：變形溫度為490 ℃時(shí)，隨著應(yīng)變速率的增加，6082鋁合金變形組織內(nèi)亞晶和位錯(cuò)密度不斷增加，再結(jié)晶程度卻不斷下降。在后續(xù)熱處理過程中，亞結(jié)構(gòu)作為析出相的有利形核點(diǎn)誘導(dǎo)形核，析出相直徑隨著位錯(cuò)密度的增加而減小，且間距變小，數(shù)量密度增加。同時(shí)，位錯(cuò)密度和亞晶體積分?jǐn)?shù)對析出強(qiáng)化的貢獻(xiàn)呈線性關(guān)系，共同影響著析出相的強(qiáng)化效果，二者達(dá)到平衡時(shí)總強(qiáng)化效果最好，即在 為0.3 s-1熱變形時(shí)，(550 ℃、1 h固溶)+(180 ℃、12 h)人工時(shí)效熱處理后，鍛件的屈服強(qiáng)度達(dá)到331.4 MPa，伸長率為9.9%。
關(guān)鍵字: 6082鋁合金；鍛壓；位錯(cuò)密度；亞結(jié)構(gòu)；析出強(qiáng)化
（1. Research Institute of Light Alloy, Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:To study the influence of substructure evolution on mechanical properties of 6082 aluminum alloy forgings, the forging tests of 6082 aluminum alloy were carried out at different strain rates. By means of EBSD and TEM characterization, the effects of subgrain volume fraction and dislocation density on precipitation strengthening were investigated under different heat treatment conditions. The results show that, when the deformation temperature is 490 ℃, the density of subgrain and dislocation in the deformed microstructure of 6082 aluminum alloy increases with the increase of strain rate, while the degree of recrystallization decreases continuously. During the subsequent heat treatment process, the substructure acts as the favorable nucleation point to induce the nucleation of the precipitated phase, and the precipitation diameter decreases with the increase of dislocation density, and the spacing becomes smaller, and the quantity density increases. At the same time, the contribution of dislocation density and subgrain volume fraction to the precipitation strengthening is linear, which affects the strengthening effect of the precipitation. When both two strength contributions reach the balance, the mechanical properties are the best after (550 ℃, 1 h solid solution)+(180 ℃, 12 h) artificial aging heat treatment, the yield strength reaches 331.4 MPa, and the elongation is 9.9%.
Key words: 6082 aluminum alloy; forging; dislocation density; substructure; precipitation strengthening
