Enhancement of Hardness of Aluminum 6063-T6 alloy by Applying Two Step Age Hardening Process

Abstract

Aluminum 6063 T6 is an alloy that is mainly used for structural applications such as window and door frames, partitioning, L bars, U bars, and ladders. It contains magnesium (0.45-0.9%) and silicon (0.2-0.6%) as the main alloying elements. T6 denotes the heat treatment process of solution treatment is followed by artificially age hardening. Age hardening process is used to improve the hardness and strength of this alloy by forming second phase particles of Mg2Si which act as a barrier for dislocation movement. This work is mainly focused on the enhancement of hardness of Aluminum 6063 T6 extrudates, and increasing the production rate while keeping the cost effectiveness. Two step age hardening treatment is developed as a substitution for the existing single step age hardening treatment applied in local industry, to reduce the total time period and temperatures while improving the hardness. In this work, average hardness value of Aluminum 6063 T6 extrudates produced in local industries is taken as the reference and that is improved up to the required level by varying the time periods and temperatures of two step age hardening process. The developed two step age hardening process is effective in terms of achieving hardness of 68.4 HV that is a significant improvement relative to the reference hardness value of 63.5 HV. The reduced total time period of 210 min and reduced second step aging temperature of 175 oC in developed two step age hardening process lead to decrease the energy consumption by 30.72% and time period by 28.57% relative to the age hardening process used in local industry.