應(yīng)力腐蝕性能的影響
(中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室, 長(zhǎng)沙 410083)
摘 要: 研究了近固溶度高溫預(yù)析出工藝對(duì)抗應(yīng)力腐蝕性能較差的中強(qiáng)可焊7A52和仿7039合金的組織、 時(shí)效硬化和應(yīng)力腐蝕性能的影響。 顯微組織觀察、 力學(xué)性能分析及應(yīng)力腐蝕性能測(cè)試結(jié)果表明： 近固溶度高溫預(yù)析出處理可使合金在晶界形成不連續(xù)的析出相； 在保持合金強(qiáng)度、 塑性的同時(shí)， 預(yù)析出可提高抗應(yīng)力腐蝕性能， 但預(yù)析出溫度過低， 合金強(qiáng)度呈下降趨勢(shì)； 固溶后于400 ℃預(yù)析出處理在峰值時(shí)效狀態(tài)下可使7A52鋁合金強(qiáng)度和抗應(yīng)力腐蝕性能得到最佳組合， 抗應(yīng)力腐蝕性能達(dá)到三級(jí)時(shí)效后的效果。
關(guān)鍵字: Al-Zn-Mg合金; 近固溶度預(yù)析出; 組織; 力學(xué)性能; 應(yīng)力腐蝕性能
（ State Key Laboratory of Powder Metallurgy, Central South University,
Changsha 410083, China）
Abstract: The effects of near-solvus high-temperature pre-precipitation on the microstructure, age hardening and stress corrosion cracking of 7A52 and quasi 7039 aluminum alloys were investigated. After analyzed by optical and transmission electron microscope, it is shown that the near-solvus pre-precipitation can be limited to grain boundary and can enhance the discontinuity of grain boundary precipitates in the sequent age. The stress corrosion cracking resistance can be improved with non-deteriorated strength and plasticity via the high-temperature pre-precipitation. The optimum combination of strength and stress corrosion cracking resistance in peak-aging temper can be obtained for 7A52 alloy after pre-precipitation treatment at 400 ℃. The stress corrosion cracking resistance at peak-aging temper can match the same effect with retrogression and re-aging Treatments by the high-temperature pre-precipitation.
Key words: Al-Zn-Mg aluminum alloy; near-solvus pre-precipitation; microstructure; mechanical property; stress corrosion cracking
