Tensile properties of 2024 Al alloy processed by enhanced solid-solution and equal-channel angular pressing
(1.江苏省镇江市江苏大学材料科学与工程学院
2.School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
3.School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China)
2.School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
3.School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China)
Abstract: Equal-channel angular pressing(ECAP) of an enhanced solid-solution treated 2024 Al alloy was successfully performed at room temperature, with an imposed equivalent normal strain of about 0.5. A very high hardness about HV191 and yield strength about 610 MPa (30% higher than those of the unECAPed 2024 Al alloy) in terms of commercial aluminum alloys were observed for the ECAPed 2024 Al alloy. In addition to the strengthening, this process allows the ECAPed 2024 Al alloy have a moderate level of tensile ductility (about 12.7%) and a significant strain hardening capability up to tensile failure. After aged at 373 K for 48 h, the ECAPed alloy increases its hardness (about HV201) and tensile ductility (about 14 %) further. The TEM results show that the ECAPed 2024 Al alloy presents a plate structure (about 50？100 nm) with high density of dislocation and additional thin plate (approximately ＜10 nm＝ inside. The XRD results show that the ECAP processing decreases the texture and increases the dislocation density of the alloy considerably. The theoretical calculations show that the increase of dislocation density resulting from ECAP processing makes a considerable contribution about 55.2 % for the improvement of yield strength.
Key words: aluminum alloy; enhanced solid-solution treatment; equal-channel angular pressing; mechanical properties