Heterostructured Al/10 vol% (TiC-GNPs) composites were produced by powder metallurgy (PM) with different TiC-to-GNPs volume ratios. As the TiC-to-GNPs ratio decreases, the improved dispersion of TiC in the matrix is achieved and the heterostructure of the composite is optimised due to the decreased TiC fraction and increased interaction between TiC and GNPs. Besides, compressive properties of the composite are improved significantly, and a balance of the significantly increased strength (σYS of 481.0 MPa and σUCS of 651.4 MPa) and reasonably remained ductility (εf of 10.9%) is achieved in the Al matrix composite reinforced with 8.5 vol% TiC and 1.5 vol% GNPs (A4) based on the optimised TiC-to-GNPs ratio and optimised heterostructure. However, the compressive properties decrease dramatically when the GNPs content reaches 2 vol% because of the presence of GNPs agglomerates.
With the increasing demands of automobile and aerospace industries, it is necessary to develop novel wear-resistant Al matrix composites (AMCs). Graphene is commonly used as an additive in self-lubricating AMCs due to its high strengthening efficiency and 2D structure. Considering the high cost of graphene and reinforcing the Al matrix by multiple reinforcements, novel Al matrix hybrid nanocomposites reinforced with B4C and in-situ GNSs were developed in this study. Al-10 vol% (x1 B4C-x2 graphite) composites (x1: x2 = 10:0, 9:1, 7:3, 5:5) were prepared by powder metallurgy. Vickers hardness tests and ball-on-disc wear tests were used to assess the mechanical and tribological properties of the composites. It is found that in-situ GNSs can be formed in Al-9 vol% B4C-1 vol% graphite (Al–9B-1G) and Al-7 vol% B4C-3 vol% graphite (Al–7B-3G) composites, thereby significantly increasing the Vickers hardness. Benefiting from the strengthening effects of B4C and in-situ GNSs, as well as the
Al-10.0 vol% (TiC and GNPs) composites were fabricated with different volume ratios of TiC and GNPs from 10.0:0.0–8.0:2.0 by powder metallurgy. The results show particle free zones (PFZs) in as-sintered composites decrease and distributions of reinforcements become more uniform, and the hardness and wear resistance of hybrid composite increase as TiC-to-GNPs ratio decreases. Al-8.5 vol% TiC-1.5 vol% GNPs has the highest hardness at 200.5 HV and the best wear resistance with a wear rate of 4.99 × 10−4 mm3/Nm based on the collaborative effects of TiC and GNPs, respectively. However, as the GNPs fraction increases to 2.0 vol%, the hardness and wear resistance of the composite drop drastically because of GNPs agglomeration.