Enhancement of tensile and fatigue properties of hybrid aluminium matrix composite via multipass friction stir processing

In present work, friction stir processing (FSP) has been used to fabricate hybrid aluminium matrix composite (HAMC) using a mixture of 6% ZrO2 and 6% Ni as reinforcement particles. Four different passes (1, 2, 4, and 6) were used to study the influence of multipass FSP on tensile properties, residual stresses, and fatigue performance of HAMCs. Six pass FSP led to significantly improved tensile properties due to more uniform distribution of reinforced particles and refined grains, and enhanced compressive residual stresses to-106 +/- 6.8 MPa compared to-9 +/- 1.8 MPa in base material. The increment in fatigue life of HAMCs is 31% (two passes), 61% (four passes), and 69% (six passes) as compared to the base material (4.08 x 105 cycles) for the lowest maximum applied stress of 100 MPa. The fatigue fracture characteristics of HAMCs with more than one FSP pass were found to be ductile-brittle mixed mode. The study concluded better fatigue life of HAMC obtained using six passes. (c) 2022 The Author(s). Published by Elsevier B.V.