(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 研究一種Al-Zn-Mg-Cu合金在連續(xù)冷卻過程中的固態(tài)相變和連續(xù)冷卻轉(zhuǎn)變曲線。通過力學(xué)性能檢測和顯微組織觀察確定臨界固溶溫度，采用連續(xù)的相對電阻法和X射線衍射法測出了該合金的相變開始點(diǎn)，結(jié)合顯微組織觀察和析出相定量分析測出了相變結(jié)束點(diǎn)，分析比較了不同冷卻速度對應(yīng)的微觀組織，通過逐步減小實(shí)驗(yàn)冷卻速度范圍逼近臨界冷卻速度。結(jié)果表明：采用連續(xù)的相對電阻法能有效地研究鋁合金的固態(tài)相變，針對不同冷卻速度范圍采用不同方法的分段綜合測試可以獲得較為完整的連續(xù)冷卻轉(zhuǎn)變曲線。
關(guān)鍵字: Al-Zn-Mg-Cu合金；連續(xù)電阻法；連續(xù)冷卻轉(zhuǎn)變曲線
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The solid phase and continuous cooling transformation(CCT) of Al-Zn-Mg-Cu alloy during continuous cooling were studied. The critical solution temperature was established by mechanical properties test and microstructures observation. The resistance testing and X-ray diffraction were used to establish the activated temperature of phase transformation. The completed temperature of phase transformation was measured by microstructures observation and quantificational analysis. The critical cooling velocity was approached by reducing the experimental cooling velocity step by step. The microstructures of samples cooled at different cooling velocity were analyzed and compared. The results show that continuous resistance testing can be utilized to study phase transformation in aluminum alloy effectively. The relatively complete CCT curves of aluminum alloy can be obtained by different methods at different cooling velocity.
Key words: Al-Zn-Mg-Cu alloy; continual resistance testing method; continuous cooling transformation curve
