A. Patil, P. R. Kalvala, R. R. Rangaraju, R. K.S., M. M., University of Nevada Reno, Reno, NV
Aluminum alloy (Al-2%Mg) surface composites were developed by incorporating silicon carbide (SiC
P) particles by friction stir processing (FSP) using a high speed steel tool pin and shoulder. Two different sizes (100-250 μm and 2 -4 μm) of SiC
P particles were used. FSP was carried out by applying 2000 rpm and a speed of 15 mm/min. After FSP, X-ray diffraction was carried out to find for any phase changes. Scanning electron microscopy (SEM) was used to characterize the particle distribution and their chemical compositions. Vickers hardness measurements were made. Pin-on-disk tests were conducted as per ASTM G-99.
The size of the coarser SiCP particles was reduced to ~ 1 μm or less by FSP from an initial size of 100 - 250 μm . In contrast, the size of the finer SiCP particles was not significantly different after FSP compared to their initial size. The distribution of particles was found to be more uniform on the surface as well in the cross sectional direction of the FSP specimens when coarser particles were used. In the case of finer particles, the density of particles was more at the bottom of FSP nugget than at the top.
XRD results showed presence of SiC and Al. SiCP particles which were distributed in aluminum matrix were found to be decorated with matrix material due to friction stirring. SEM and EDS results of FSP samples showed the presence of Fe and W in surface composite which was confirmed due to the wear of tool material. Hardness of aluminum alloy base material increased from 60 Hv to 258 Hv after FSP. Pin-on-disk tests showed that wear loss of FSP specimens was negligible compared to the extensive wear of base plate. There was no difference between the wear resistance of pins made of two sizes of SiCP particles.
Aluminum alloy (Al-2%Mg) surface composites were developed by incorporating silicon carbide (SiCP) particles by friction stir processing (FSP) using a high speed steel tool pin and shoulder. Two different sizes (100-250 μm and 2 -4 μm) of SiCP particles were used. FSP was carried out by applying 2000 rpm and a speed of 15 mm/min. After FSP, X-ray diffraction was carried out to find for any phase changes. Scanning electron microscopy (SEM) was used to characterize the particle distribution and their chemical compositions. Vickers hardness measurements were made. Pin-on-disk tests were conducted as per ASTM G-99.
The size of the coarser SiCP particles was reduced to ~ 1 μm or less by FSP from an initial size of 100 - 250 μm . In contrast, the size of the finer SiCP particles was not significantly different after FSP compared to their initial size. The distribution of particles was found to be more uniform on the surface as well in the cross sectional direction of the FSP specimens when coarser particles were used. In the case of finer particles the density of particles was more at the bottom of FSP nugget than at the top.
XRD diffractogram confirmed the presence of SiC peaks along with aluminum peaks indicating no other phases formed due to FSP in Al- SiCP surface composite. SiCP particles which were distributed in aluminum matrix were found to be decorated with matrix material due to friction stirring. SEM-EDS of few SiCP particles in the FSP samples showed the presence of Fe and W indicating the wear of tool material. This was confirmed by wear of tool by SEM examination. Hardness of aluminum alloy base material increased from 60 Hv to 258 Hv after FSP. Pin-on-disk tests showed that wear loss of FSP specimens was negligible compared to the extensive wear of base plate. There was no difference between the wear resistance of pins made of two sizes of SiCP particles.
