Characterization of in Situ Surface Composite Al-Al3Ni-Tic by Friction Stir Processing With Inserting Maed Powder

In this study, in situ Al-Al3Ni-TiC surface composite was successfully fabricated by friction stir processing (FSP) of AA1050 alloy. For this purpose mechanically alloyed Ni-Ti-C powder mixture prepared by high energy milling for a total duration of 20h, was inserted into Al substrate. Microstructure, microhardness and wear behavior of the composites obtained from 2 and 6 FSP passes were evaluated. Microstructural examinations of MAed powder and composite were performed using an optical microscope (OM) and scanning electron microscope (SEM) equipped with microprobe elemental analysis. The results of the experiments showed that in situ reaction occurred between MAed powder and matrix during friction stir processing and resulted in the formation and distribution of Al3Ni and TiC compounds in the matrix. Al3Ni and TiC compounds increased the hardness and improved the wear resistance of in situ composites.The hardness of the composite obtained from 6 FSP passes (70 HV) increased about 280% compared to the base metal (≈25 HV). The composite obtained from 2 FSP passes showed non-uniform hardness due to incomplete reaction and inhomogeneous distribution of powder particles. The dominant wear mechanisms were identified as abrasive wear and adhesive wear for the base metal and composite obtained from 2 FSP passes, and abrasive wear for the composite obtained from 6 FSP passes.