The effects of sintering and shot peening processes on the fatigue strength

Alumix 431 metal powders have been used in this study since they are widely used in the industrial applications. First, Alumix 431 powders were compacted at 400 MPa pressure under room temperature (RT). Then, pressed specimens were sintered separately at 600 and 620 degrees C for 1h N-2. Densities were measured for the different temperatures in order to examine the effects of the sintering on density. Improvement of green density was observed to have enhanced approximately 86 and 90% according to theoretical density (2, 786 g/cm(3)) as a result of the sintering condition at 600 and 620 degrees C, respectively. After sintering a group of specimen was shot peened with the intensities in 12 and 16A. To investigate mechanical properties of as sintered (unpeened) and shot peened samples, tensile and fatigue tests were performed. It was determined that shot peening improved the fatigue strength about 10 and 15% in 12 and 16A intensities, respectively. In addition, fractured specimens after tensile tests were used for Micro-Hardness measurements, and for metallographic analysis by, optical microscopy (OM) and scanning electron microscopy (SEM) tests further specimens were examined.