Effect Of Si, Mg, Sr And Ce On The Recovery Properties Of4043Aluminum Alloy Wire

This paper mainly researched the effect of adjusting Si, adding Mg and modifier Sr, Ce on the recovery properties of4043aluminum alloy wire, the best component of the wire was determined by comparing the microstructure, mechanical properties and wear resistance of the welded joint and surfacing metal, and the best component of the surfacing metal in different aging temperature was studied to determine the best treatment process.The wires were produced in the Key Laboratory Electromagnetic Processing of Materials Northeastern University. Butt welding and surfacing were made by AC-TIG, and the different component of the welded joints were compared by the microstructure, hardness and tensile properties, and the different component of the surfacing metals were compared by microstructure, hardness and wear resistance. The best component of surfacing metal was solutionized at540℃for4h, followed by water quenching(30℃) and aging hardening at140℃,170℃and210℃respectively, and the wear resistance of the surfacing metals were compared in the differnt treatment process.The results showed that the increase in Si (wt.%) improved the tensile strength and yield strength of the welded joints. The columnar crystals in the weld seam became narrow and the orientation was more obvious with the addition of the modifier Sr, while the tensile strength and yield strength of the welded joint also increased by12.3%and15.7%respectively. The tensile strength and yield stength of the welded joint increased obviously when adding Mg. The tensile strength and yield strength achieved the highest when adding0.3%Mg. The columnar crystals in the weld seam became narrow with the addition of the modifier Ce, and the small amplitude improvement of strength was achieved. The distribution of hardness of the HZ, FZ and WAZ was roughly same as the "W". The increase in Si (wt.%) improved the hardness of the welded joint, and the hardness of the welded joint was increased by the adding of Sr. The hardness of the welded joint increased obviously when adding Mg, and the hardness achieved the highest when adding0.3%Mg. The hardness increased little when adding the modifier of the Ce. As a result, the best component of the wire was5.9%Si+0.3%Mg+0.06%Sr.The hardness of the surfacing layer increased, the friction coefficient and the volume of wear decreased with the increase in Si (wt.%). The morphology of the eutectic silicon changed from the sparse distributed acicular euectic silicon to dispersive distrbuted fibers, and the hardness of surfacing layer increased, the friction coefficient and the wear volume decreased when adding the modifier Sr. The friction and wear volume with the addition of0.8%Ce is more than the addition of0.06%Sr when the volume of the Si and Mg is same. As a result, the best component of the wire was5.9%Si+0.3%Mg+0.06%Sr.The spheroidized eutectic silicon particles strengthened the combine between the α-Al and eutectic silicon particles due to the heat treatment. The hardess increased, the friction coefficient and the wear volume decreased obviously than the untreatment surfacing layer when the aging temperature is140℃. The highest hardness, the lowest friction coefficient and wear volume were achieved when the aging temperature is170℃, and it reached111.1HV,0.346å'Œ0.0045g respectively. The surfacing layer is overaging when the aging temperature is210℃, and the hardness is even lower,the friction coefficient and wear volume is much higher than the untreatment. As a result, the best wear resistance of treatment process is540℃/4h+water quenching(30℃)+170℃/12h.