(1. 中南大學(xué)物理與電子學(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)與工程教育部重點實驗室，長沙410083)
摘 要: 采用差示掃描量熱分析確定Al-Zn-Mg-Zr合金均勻化處理溫度和過燒溫度，采用光學(xué)顯微鏡、掃描電鏡、能譜分析和透射電鏡研究合金鑄錠均勻化過程中顯微組織的演化，探索該合金的均勻化熱處理工藝，研究鑄錠均勻化動力學(xué)過程，并利用菲克定理構(gòu)建均勻化動力學(xué)方程。結(jié)果表明：鑄態(tài)Al-Zn-Mg-Zr合金由α(Al)固溶體、固溶了Cu元素的η-MgZn2相和非平衡共晶相T-Mg32(Al, Zn)49組成。隨著均勻化溫度的升高和時間的延長，非平衡共晶相溶入基體，晶內(nèi)有彌散Al3Zr粒子析出，該合金的最佳均勻化熱處理工藝為470℃退火16h。
關(guān)鍵字: Al-Zn-Mg-Zr合金；鑄錠；均勻化；顯微組織；動力學(xué)
（1. School ofPhysics and Electronics, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education,
School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The homogenization temperature and overburnt temperature of an Al-Zn-Mg-Zr alloy ingot were confirmed by differential scanning calorimetry, the microstructure evolution of the alloy during homogenization was investigated by optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive X-ray spectrometry(EDX) and transmission electron microscopy(TEM). And the homogenization kinetics equation was derived by theFick’s law. The results show that the ingot of Al-Zn-Mg-Zr alloy contains a large mount of second solidifying phases, skeletal MgZn2 phase and T-Mg32(Al，Zn)49 phase, which distribute on the boundaries。The second phases are gradually dissolved into the matrix, and the grain boundaries become spare and thin during homogenization with the increase of the temperature and holding time. The results of homogenization kinetic equation and annealing experiments for the Al-Zn-Mg-Zr alloy both show that (470℃, 16h) is the optimal homogenizing treatment process.
Key words: Al-Zn-Mg-Zr alloy; ingot; homogenization; microstructure; kinetics
