(中南大學(xué) 材料科學(xué)與工程學(xué)院, 長(zhǎng)沙 410083)
摘 要: 利用透射電鏡和硬度測(cè)量實(shí)驗(yàn)手段，研究了強(qiáng)變形誘導(dǎo)析出相回歸后的合金在再時(shí)效過程中的組織、 性能變化。 發(fā)現(xiàn)： 多相合金Al-Zn-Mg-Cu經(jīng)固溶、 時(shí)效處理后， 析出相粒子在強(qiáng)變形過程中破碎細(xì)化并可重新回歸于基體內(nèi)。 強(qiáng)變形導(dǎo)致回歸后的合金在再時(shí)效處理時(shí)可再次沉淀析出第二相粒子，但析出相的析出順序與強(qiáng)變形后合金的晶粒尺有相關(guān)， 當(dāng)晶粒細(xì)化到某一臨界尺寸以下時(shí)， 析出順序發(fā)生改變， 非均勻形核的平衡相可抑制GP區(qū) 、 η′亞穩(wěn)相等前期粒子的析出。
關(guān)鍵字: 強(qiáng)變形; Al-Zn-Mg-Cu合金; 時(shí)效析出相; 回歸; 再時(shí)效
ZHENG Qing-chun, YE Cheng-wu
（ School of Materials Science and Engineering,
Central South University, Changsha 410083, China）
Abstract: The microstructure and properties of an aged Al-Zn-Mg-Cu alloy associated with severe plastic deformation were studied by transmission electron microscopy and hardness measurement methods. The results show that the precipitates is fragmented and the retrogressive phenomenon of precipitated phase particles is caused by severe plastic deformation at room temperature condition. The sample which has retrogressive phenomenon precipitates the secondary phase during re-ageing treatment subsequently, and the reprecipitation sequence is due to the grain size caused by severe plastic deformation. There is a critical grain size below which the reprecipitation sequence changes, the heterogeneous precipitation of phase at grain boundaries would suppress precipitation of metastable phases such as GP zones and η′ phase.
Key words: severe plastic deformation; Al-Zn-Mg-Cu alloy; ageing precipitated phase; retrogression; re-ageing
