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

摘要

Effects of Mn addition on microstructure and mechanicalrnproperties of as-cast and as-extruded Al-0.15Si-0.2Fe-0.3Cu-rn0.15Zn-xMn alloys were investigated. After the as-cast billetsrnwere kept at 400 ℃ for 1 h, hot extrusion was carried out with arnreduction ratio of 38:1. Mn addition to Al-0.15Si-0.2Fe-0.3Cu-rn0.15Zn based alloys resulted in the formation of Al_6(Fe,Mn) andrnAl_(15)(Fe,Mn)_3Si_2 intermetallic compounds and grain refinement.rnWith increasing of addition of Mn, yield strength and ultimaterntensile strength was increased and maximum value of yieldrnstrength and ultimate strength was 29 and 96 MPa at 2.1 Mnrncontaining alloy, respectively. In the tensile properties at 420 ℃,rnMn containing intermetallic compounds plays an important rolernfor the improvement of strength and elongation due to grainrnrefinement and suppression of grain growth by the formation ofrnthermally stable Mn containing intermetallic compounds.