(華中科技大學(xué) 材料科學(xué)與工程學(xué)院 材料成形與模具技術(shù)國家重點(diǎn)實(shí)驗(yàn)室，武漢 430074)
摘 要: 采用透射電子顯微鏡、單向拉伸力學(xué)性能測試和掃描電子顯微鏡等方法研究了2195鋁鋰合金在不同形變熱處理下時效析出行為，并闡明了析出相強(qiáng)化機(jī)理。結(jié)果表明：不同形變熱處理下2195鋁鋰合金中主要強(qiáng)化相均為T1相，但是其尺寸、分布、數(shù)量密度和晶界形貌有差異。預(yù)應(yīng)變可顯著提高T1相的形核率并加速其長大過程。時效溫度越高，T1相的形核率越低，但長大速度越快。形變熱處理后的微觀組織可顯著提高2195鋁鋰合金的力學(xué)性能，T871態(tài)(固溶處理+7%預(yù)應(yīng)變+(120 ℃、4 h)+(160 ℃、24 h))的屈服強(qiáng)度為(541±10) MPa，抗拉強(qiáng)度為(606±9) MPa，伸長率為(11±1)%。位錯在T1相多處沿著垂直于直徑方向剪切，有效阻止了微觀尺度上的塑性局部化。
關(guān)鍵字: 2195鋁鋰合金；微觀組織；形變熱處理；力學(xué)性能
（State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract:In this paper, the microstructure and mechanical properties of 2195 Al-Li alloy under different thermo-mechanical processing(TMP) were studied by transmission electron microscope, uniaxial tensile mechanical property test and scanning electron microscope. The aging precipitation behavior was analyzed and the strengthening mechanism of precipitates was clarified. The results show that the main strengthening phase under different TMP is T1 phase, but its size, distribution, quantity density and grain boundary morphology are different. Pre-strain can significantly increase the nucleation rate of T1 phase and accelerate its growth process. The higher the aging temperature, the lower the nucleation rate of T1 phase, but the faster the growth rate. Microstructures formed by TMP can significantly improve the mechanical properties of 2195 Al-Li alloy. The yield strength, tensile strength and elongation of T871 state (solution treatment+7% pre-strain+(120 ℃, 4 h)+(160 ℃, 24 h)) are (541±10) MPa, (606±9) MPa and (11±1)%, respectively. The dislocation shears along the direction perpendicular to the diameter of T1 phase at multiple locations, which effectively prevents plastic localization on the micro-scale.
Key words: 2195 Al-Li alloy; microstructure; thermo-mechanical processing; mechanical property
