STUDY THE MICROWAVE ENERGY EFFECTS ON MECHANICAL PROPERTIES AND ESTIMATED FATIGUE LIFE OF AA7075-T6

الملخص

This study is concerned with the effect of microwave heat treatment of AA7075-T6 on mechanical properties and fatigue life. Specimens were divided into four groups, firstly, specimens were subjected for 60 min. of microwave heat as a dry, secondly, specimens were subjected for 30 min. of microwave heat as a dry, thirdly, specimens were subjected for 60 min. of microwave heat as a wet, and fourthly, specimens were subjected to 30 min. of microwave heat as a wet condition. Then, it is compared with the original alloy (AA7075-T6). The mechanical tests that are used in this research are tensile, hardness, surface roughness, and fatigue. It is found that the hardness of dry specimens is higher than wet specimens, and hardness of dry condition for 60 min. has higher enhancement (15%) as compared with the original alloy. Hardness is increased with increasing of time inside the microwave. However, the tensile strength of wet conditions has higher than dry conditions; also, tensile strength is increased with decreasing of time inside microwave furnace. Ultimate and yield strength of wet condition for 30 min. have 55% and 99% respectively, enhancement as compared with AA7075-T6. The surface roughness parameter (Ra) of dry conditions has higher than wet conditions and then decreases as decreasing of time inside the microwave furnace. Fatigue strength results showed that decreasing as compared with original alloy.