(1. 江蘇工業(yè)學院 材料科學與工程學院，常州 213164；
2. 中南大學 材料科學與工程學院，長沙 410083)
摘 要: 采用拉伸試驗、晶間腐蝕試驗、金相及透射電鏡觀察，研究雙級時效對6061鋁合金拉伸性能和晶間腐蝕性能的影響。結(jié)果表明：6061鋁合金經(jīng)(180 ℃, 8 h)的T6峰值時效，抗拉強度和屈服強度分別為356 MPa和331.6 MPa，伸長率為13.7%，但出現(xiàn)嚴重的晶間腐蝕，腐蝕深度約為270 mm。在T6峰值時效的基礎(chǔ)上進一步升高溫度和延長時間進行二級時效，合金強度總體上呈逐漸降低趨勢，電導率逐漸上升，腐蝕類型也由晶間腐蝕逐漸轉(zhuǎn)變?yōu)辄c蝕，腐蝕深度明顯變淺。對于6061鋁合金，最佳雙級時效工藝為(180 ℃, 8 h)+(210 ℃, 2 h)，抗拉強度為348.4 MPa，屈服強度為320.3 MPa，伸長率為11.3%，腐蝕類型為輕微點蝕，腐蝕深度約為50 mm。
關(guān)鍵字: 6061鋁合金；雙級時效；晶間腐蝕；微觀組織
（1. School of Materials Science and Engineering, Jiangsu Polytechnic University, Changzhou 213164, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Effects of two-step ageing treatment on tensile properties and intergranular corrosion(IGC)of 6061 aluminum alloy were investigated by tensile test, intergranular corrosion test, optical microscopy and TEM observation. The experimental results show that ultimate tensile strength, yield strength and elongation of 6061 alloy in T6 temper are 348.4 MPa, 320.3 MPa and 13.7%, respectively. However, the serious intergranular corrosion occurs with corrosion depth of about 270 mm. As a result of two-step ageing treatment, the strength decreases and the conductivity increases with the increase of two-step ageing temperature and time, but the mode of corrosion changes from intergranular corrosion to pitting corrosion (PC) while the corrosion depth decreases. Under the optimum two-step ageing treatment of (180 ℃, 8 h)+(210 ℃, 2 h), the ultimate strength, yield strength and elongation are 348.4 MPa, 320.3 MPa and 11.3%, respectively. The mode of corrosion is slight pitting with corrosion depth of 50 mm.
Key words: 6061 aluminum alloy; two-step ageing; intergranular corrosion; microstructure
