Effects of Alloying Elements on Microstructure, Mechanical Properties and Formability of Al-Si-Fe-Cu-Mn Based Alloys for Micro-Channel Tube of Heat Exchanger

Abstract

Effects of Mn addition on microstructure and mechanical properties of as-cast and as-extruded Al-0.15Si-0.2Fe-0.3Cu-0.15Zn-xMn alloys were investigated. After the as-cast billets were kept at 400 °C for 1 h, hot extrusion was carried out with a reduction ratio of 38:1. Mn addition to Al-0.15Si-0.2Fe-0.3Cu-0.15Zn based alloys resulted in the formation of Al₆(Fe,Mn) and Al₁₅(Fe,Mn)₃Si₂ intermetallic compounds and grain refinement. With increasing of addition of Mn, yield strength and ultimate tensile strength was increased and maximum value of yield strength and ultimate strength was 29 and 96 MPa at 2.1 Mn containing alloy, respectively. In the tensile properties at 420 °C, Mn containing intermetallic compounds plays an important role for the improvement of strength and elongation due to grain refinement and suppression of grain growth by the formation of thermally stable Mn containing intermetallic compounds.