Effect of Machining Process Conditions on Fatigue Behavior of Magnesium Alloy AZ61

抄録

The cantilever rotating bending fatigue tests were conducted using extruded wrought magnesium alloy, AZ61, specimens, which were made by the machining process under two different conditions, and the surface effect by machining process on the fatigue behavior was investigated. By the machining process, the grains near the surface were refined, the hardness increased, and the compressive residual stress was given. When the specimens were machined under severer condition where rake angle and cut depth were large, and feed rate and cutting speed were low, the depth of grain refinement area became deeper, the hardness was higher, and the absolute value of residual compressive stress was higher than the specimens machined under the conventional condition. The specimens having the work-affected layer near the surface by the machining process exhibited the higher fatigue strengths than the specimens in which the work-affected layer was totally removed by polishing. The severer machining condition resulted in the higher fatigue strengths. The fatigue lives became shorter with the increase of the polishing depth of the work-affected layer, which indicated that the thicker work-affected layer was more effective to improve the fatigue strengths.