| The effects of Mn addition and homogenization heat treatment on the tensile properties in as-extruded Al-Mg-Si-Mn alloys have been studied to develop a new Mn bearing alloy without heat treatment after the extrusion process. When the ingots were hot extruded at 450℃ with constant extrusion ratio(9:1) and speed (10 ㎜/sec), the optimum condition for extrusion press effect, which results in improvement of strength due to the formation of texture, was found to be the largest. Three kinds of homogenization heat treatment were conducted to determine the optimum condition for the extrusion process. Adding manganese to Al-Mg-Si based alloy in the range of 0.2wt.%∼1.0wt.%, Mn-dispersoids composed of Al, Mn and Si was formed. Though the size and the density of Mn-dispersoid were somewhat reduced after extrusion process, as the content of Mn was increased, the density of Mn-dispersoid was increased. Also homogenization heat treatment affected the size and the distribution of Mn-dispersoid before and after extrusion process. The effect of Mn addition on the tensile properties was small in peak aged condition of 1.0wt.%Mn bearing alloy but the properties were improved by the combination of the addition of Mn and the homogenization heat treatment in as-extruded state. |
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