Publication

Abstract : This study compares a conventional single-shoulder tool with a novel double-step shoulder tool for processing TiN- and hBN-reinforced AA5754 surface composites. The results demonstrated that the additional shoulder improved surface quality by increasing frictional heat generation, promoting material flow, and enhancing the distribution of reinforcing particles throughout the matrix. It also restricted grain growth and reduced the size of reinforcing particles and agglomerates. Consequently, the tensile strength increased from 148.57 to 183.54 MPa, corresponding to an improvement of approximately 23.5%, while the hardness increased from 113 to 131 HV. Moreover, the wear rate and coefficient of friction decreased to 0.28 mm3/N·m and 0.36 ± 0.01, respectively. These improvements were attributed to the more uniform distribution of reinforcing particles and the pronounced grain refinement achieved throughout the stirred zone.