Study on the microstructure and mechanical properties of Al matrix composites reinforced with nano Ni via friction stir processing

Achieving simultaneous improvement in both strength and ductility remains a significant challenge in the development and application of aluminum matrix composites (AMCs). This study uses shift-speed ball milling (SSBM) combined with multipass friction stir processing (FSP) to fabricate nano Ni-reinforced 1060 Al composite to form the intermetallic. According to the study, nano Ni was dispersed into Al uniformly through SSBM and then formed Al 3 Ni after multipass FSP. In situ generated Al 3 Ni further enhances the effects of nano Ni in grain refinement strengthening, Orowan mechanism, and load transfer of scattered reinforcement. The uniform dispersion of in situ Al 3 Ni particles results in strong interfacial bonding and refined microstructure in the AMCs to achieve improvement in both strength and ductility. Among all samples, AMCs reinforced by 10 wt% Ni exhibit 184.6 MPa in ultimate tensile strength, 66.1 HV in hardness, and 20.1 % in elongation, which increases 103.8 %,120.3 %, and 32.2 % than the base metal. As the content continues to increase to 15 wt%, partial agglomeration of Ni may affect the mechanical properties. The research can provide fundamental insights and ideas to enhance the mechanical properties of FSPed AMCs.