Effect of Heat Treatment on Notch Sensitivity Factor for Aluminum Alloys


This study is concerned with the effect of heat treatment (precipitationhardening) on notch sensitivity factor for aluminum alloy (7075). Tests wereconducted on four configurations of specimens, three of them which had externalcircumferential notches with notch radii of 0.5 mm, 0.7 mm, and 1 mm. Thefourth configuration is un-notched specimens. The alloy samples which were usedin fatigue test were subjected to cold working before heat treatment. Dimensionsand roughness of the specimens were measured. The fatigue tests were performedfor different types of specimens. The (S-N) equation was derived for each group toestimate the fatigue life under any applied stress amplitude. In addition, thestrength reduction factor (kf )and notch sensitivity factor (q) were calculated.The results showed that the fatigue strength reduction factor wereincreased after heat treatment and with decreasing notch radius. Also the notchsensitivity factor increased with increasing notch radius and after heat treatment.The enhancement percentage in notch sensitivity factor after the heat treatment for1 mm radius notch was (22.616%).