(1. 中南大學(xué)材料科學(xué)與工程學(xué)院，長沙 410083；
2.中南大學(xué)材料科學(xué)與工程學(xué)院有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 通過光學(xué)顯微鏡、掃描電鏡、透射電鏡、強(qiáng)度實(shí)驗(yàn)、沖擊韌度實(shí)驗(yàn)、應(yīng)力腐蝕實(shí)驗(yàn)、剝落腐蝕實(shí)驗(yàn)及極化曲線測(cè)試，研究不同微量元素(Cr、Mn、Ti、Zr、Cu)含量添加對(duì)Al-Zn-Mg鋁合金組織、力學(xué)性能與腐蝕性能的影響。結(jié)果表明：較多的微量元素使得合金內(nèi)部第二相析出密度變大，對(duì)亞晶界/晶界的遷移起阻礙作用而未誘發(fā)粒子形核，提升合金抑制再結(jié)晶的能力，從而保持細(xì)小晶粒及亞晶組織，合金的抗拉強(qiáng)度提升69MPa，應(yīng)力腐蝕開裂延遲了108h。但同時(shí)微量元素使得AlFeMnCu等粗大的第二相增多，使自腐蝕電位正移、腐蝕電流密度變小，而塑性、韌性及耐剝落腐蝕性能均有所下降。
關(guān)鍵字: Al-Zn-Mg鋁合金；微量元素；力學(xué)性能；腐蝕性能；電化學(xué)性能
（1.School of Materials Science and Engineering, Central South University, Changsha410083, China;
2.Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education,
School of Material Science and Engineering, Central South University, Changsha410083, China）
Abstract:The effects of different microelement(Cr, Mn, Ti, Zr, Cu)contents on the microstructure, mechanical properties and corrosion properties of Al-Zn-Mg aluminium alloys were investigated by optical microscopy,scanning electron microscopy,transmission electron microscopy,tensile test, impact properties test, stress corrosion and polarization curve measurement．The results show that a little more microelement added to the Al-Zn-Mg aluminium alloys effectively delays the mergence and growth of the sub-grain during the recovery process, inhibits the recrystallization capability of Al matrix,and significantly enhances the mechanical properties and resistance to stress corrosion increasing the tensile strength by 69MPa and postpones the moment of stress corrosion cracking for 108h.However, the present of more trace elements makes wider distribution of the slightly larger size AlFeMnCu phase generate inside the alloy, makes the matrix as the anode form a microcell, and the surface pitting, plasticity, toughness and corrosion resistance decrease.
Key words: Al-Zn-Mgaluminiumalloy; microelement; mechanicalproperty; corrosionproperty;electrochemicalperformance
