(1. 湖南工業(yè)大學(xué) 冶金工程學(xué)院，株洲 412007；
2. 湖南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410082；
3. 湖南大學(xué) 湖南省噴射成形技術(shù)及應(yīng)用重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410082)
摘 要: 基于常規(guī)熱軋工藝對(duì)噴射成形高鎂鋁合金擠壓坯進(jìn)行單道次大應(yīng)變熱軋變形，采用透射電鏡(TEM)、掃描電鏡電子背散射成像技術(shù)(EBSD)和X衍射(XRD)方法來分析合金微觀結(jié)構(gòu)，并對(duì)比研究合金的力學(xué)性能。結(jié)果表明：噴射成形高鎂鋁合金在熱軋變形過程中，隨著變形程度的增大，位錯(cuò)密度顯著增大，位錯(cuò)胞、非平衡小角度晶界(LAGB)及亞晶顯著增多；當(dāng)熱軋變形80%時(shí)，高位錯(cuò)密度晶粒中的小角度晶界轉(zhuǎn)變?yōu)榇蠼嵌染Ы?HAGB)，亞微米級(jí)動(dòng)態(tài)再結(jié)晶晶粒大量形成，晶粒組織顯著細(xì)化，合金的室溫拉伸強(qiáng)度和伸長(zhǎng)率分別為619 MPa和19.8%。噴射成形高鎂鋁合金大應(yīng)變熱軋變形過程中的主要強(qiáng)化機(jī)制是細(xì)晶強(qiáng)化、位錯(cuò)強(qiáng)化和固溶強(qiáng)化，對(duì)變形80%合金屈服強(qiáng)度的貢獻(xiàn)值分別為120 MPa、208 MPa和158 MPa，共占總強(qiáng)度值的94.4%。
關(guān)鍵字: Al-Mg合金；噴射成形；大應(yīng)變熱軋；顯微組織；力學(xué)性能
（1. School of Metallurgical Engineering, Hunan University of Technology, Zhuzhou 412007, China;
2. College of Materials Science and Engineering, Hunan University, Changsha 410008, China;
3. Hunan Provincial Key Laboratory of Spray Deposition Technology and Application, Hunan University, Changsha 410008, China）
Abstract:The extrusion preform of the spray-forming Al alloy with high Mg content is hot rolled by 1-pass large deformation based on the conventional rolling technology. By transmission electron microscopy (TEM), electron backscatter diffractometry (EBSD) and X-ray diffractometry (XRD), the microstructure and mechanical properties of the alloy were investigated. The results indicate that the density of dislocation and the amount of dislocation cells, non-equilibrium low angle grain boundaries (LAGB) and subgrains increase with the increase of deformation during the hot rolling process. At the hot rolling deformation of 80%, the LAGB among the grains with high dislocation density transforms into high angle grain boundaries (HAGB), a large number of submicron dynamic recrystallization grains form, and the grains are significantly refined. The tensile strength and elongation at the room temperature of the alloy reach 619 MPa and 19.8%, respectively. The main strengthening mechanisms of the spray-forming Al alloy with high Mg content during the large hot rolling process are fine grain strengthening, dislocation strengthening and solid solution strengthening, the contribution of which to the yield strength of the alloy with 80% deformation are 120, 208 and 158 MPa, respectively, reaching 94.4% of the total strength.
Key words: Al-Mg alloy; spray forming; large strain hot rolling; microstructure; mechanical property
