S. Akhavan - Engineering Group, Material Engineering Department,Isfahan university of technology
A.R Saghaiannejad
A. Tahvilian - M.Sc. in Material Science & Engineering, Isfahan university of technology, Isfahan, Iran
F. Ashrafizadeh - Prof. in Material Science & Engineering, Isfahan university of technology, Isfahan, Iran

Generally it is important to control the microstructure for improving material properties. Hence, several researches have been done to improve structure and mechanical behavior of materials in sub-micron grain size at recent years. Grain atomizing is an effective and economical method to improve the mechanical properties of materials. In this study a thickness reduction of about 85% was applied on Aluminum 5083 H112 sheet by cold rolling.Then samples were heat treated at different temperatures. The microstructure changes were tested by optical microscopes. In order to analyze the mechanical properties; the samples wereapplied to mono-axis tensile, hardness and wear tests. Also the investigation of fracturesurface of samples for tensile tests and microstructure was done by SEM.The results showedthat the critical temperature in micro-structure changes is 250 °c. Also at this temperature a static recrystalization takes place which starts at 200°c.The result of wear test showed that friction coefficient near to static recrystalization process increase slightly which in accordance with temperature increase it starts to decrease. Samples hardness by effect of heat treatment at 250°c, increase then it starts to decrease. Also the fracture surface results show that a mixture of tear ductile dimples at recrystalization temperature leads to rupture

recrystalization, Aluminum 5083 H112, hardness, structure, Heat treat