( 1. 南京航空航天大學(xué) 機(jī)電工程學(xué)院, 南京 210016;
2. 北京航空材料研究院, 北京 100095)
摘 要: 在溫度400～500 ℃、 初始應(yīng)變速率為2.0×10-4 ～2.0×10-2 s-1的條件下， 對(duì)Al-6Mg-0.2Sc合金冷軋板材(初始晶粒尺寸為25 μm)進(jìn)行了相應(yīng)的超塑性能、 高應(yīng)變速率超塑性脹形成形實(shí)驗(yàn)研究。 結(jié)果表明： 在450 ℃、 初始應(yīng)變速率為2.0×10-2 s-1的實(shí)驗(yàn)條件下, Al-6Mg-0.2Sc合金冷軋板材具有高應(yīng)變速率的超塑性能, 其最大延伸率為421%; 在高應(yīng)變速率條件下, 脹形成形大端直徑為d154 mm， 深度h為80 mm的錐形零件的成形時(shí)間為73 s, 成形后零件的壁厚變薄的不均勻率小于8%。 此外, 還對(duì)成形零件的微觀組織進(jìn)行了初步的SEM觀察分析。 結(jié)果表明， 成形零件的微觀組織無明顯粗化， 其孔洞率小于1.5%。
關(guān)鍵字: Al-6Mg-0.2Sc合金; 高應(yīng)變速率超塑性; 超塑性脹形; 微觀組織
Al-6Mg-0.2Sc alloy
ZUO Dun-wen1, WANG Min1
（ 1. College of Mechanical and Electrical Engineering,
Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
2. Beijing Institute of Aeronautical Materials, Beijing 100095, China）
Abstract: The superplastic properties of a cold-rolled Al-6Mg-0.2Sc alloy were studied in the temperature range of 400-500 ℃ and strain rates range of 2.0 ×10-4-2.0×10-2 s-1 with a maximum elongation-to-failure of 308% recorded at 450 ℃ and an initial strain rate of 2.0×10-2 s-1. At the same time, high strain rate superplastic (HSRS) bulging of a cold-rolled Al-6Mg-0.2Sc alloy sheet was investigated at 450 ℃ and an initial strain rate of 2.0×10-2 s-1. The forming time of a cone-shaped part (diameter of 154 mm) is 73 s and nonuniformity of wall thickness is less than 8%. Besides, fracture microstructure of sample was examined using both optical and scan electron microscope. The results show that the grain is not coarsened and the cavity rate is less than 1.5%.
Key words: Al-6Mg-0.2Sc alloy; high strain rate superplasticity; superplastic bulging; microstructure
