【摘要】：采用電導(dǎo)率實(shí)驗(yàn)與慢應(yīng)變速率拉伸實(shí)驗(yàn)研究自然時(shí)效對Al-Zn-Mg合金型材應(yīng)力腐蝕斷裂的影響,通過掃描電鏡、透射電鏡等顯微組織分析揭示其性能變化的機(jī)理。結(jié)果表明:Al-Zn-Mg合金型材的電導(dǎo)率隨著自然時(shí)效時(shí)間的延長呈下降趨勢,停放至28 d左右基本達(dá)到穩(wěn)定狀態(tài),穩(wěn)定后合金的內(nèi)、外表層電導(dǎo)率分別為32.20(IACS)%與31.50(IACS)%。自然時(shí)效后再進(jìn)行人工時(shí)效((90℃,12 h)+(169℃,11 h)),Al-Zn-Mg合金型材的抗拉強(qiáng)度(R_m)隨自然時(shí)效時(shí)間的延長而顯著降低,但合金的抗應(yīng)力腐蝕性能明顯提高;自然時(shí)效后,合金內(nèi)晶界無沉淀析出帶變寬(PFZ),晶界析出相尺寸與間距變大。
[Abstract]:The effect of natural aging on stress corrosion cracking of Al-Zn-Mg alloy profile was studied by electrical conductivity test and slow strain rate tensile test. The mechanism of properties change was revealed by SEM and TEM. The results show that the conductivity of the alloy profiles decreases with the prolongation of natural aging time, and reaches a stable state at about 28 days. The conductivity of the outer layer of the alloy is 32.20 (IACS)% and 31.50 (IACS), respectively. After natural aging, the tensile strength (Rm) of artificial aging (90 鈩，

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