Research On Fabrication And Properties Of CNTs/ZL114Composites

CNTs/ZL114composites have been fabricated by adding CNTs as the mixture of CNTs and metal podwers preform block process (called preform block process) and preform block compound stirring process respectively. The as-cast microstructure and mechanical of properties have been observed and tested. And the composites prepared by preform block compound stirring process were treated with T6heat treatment, and it’s microstructure and mechanical properties have also been observed and tested. Fracture and interface between CNTs and matrix were observed by EDS and SEM. The impact of CNTs on the wear resistance of composite have also been investigated, the friction coefficient and mass loss of the composite have been tested. The morphology of honing and wear surface were observed by SEM and the form of wear was studied. In addition, the impact of the block compound stirring process on the distribution of CNTs in aluminum alloy have been studied.The results show that:CNTs can refine the grains of the composite, reduce the secondary dendrite arm spacin of the composite. Adding CNTs can significantly improve mechanical properties of the as-cast composite.The tensile strength and micro-hardness both reach the maximum at the CNTs addtion of1.0wt%. The value of composite prepared by preform block process are196.204MPa and84.5HV, increase by24.5%and12.7%respectively, compared with the matrix alloy, while the composites prepared by preform block compound stirring process reach204.205MPa and88.3HV. The impact of CNTs on the composites after T6heat treatment are the same as the as-cast composites, After T6heat treatment, the tensile strength and the micro-hardness increase significantly, when the amount of CNTs added1.0wt%, the tensile strength and micro-hardness reach308.904MPa and118.4HV, which increase51.3%and34.1%respectively compared with the as-cast composites. The fracture mode of as-cast composites mainly consist of the cleavage plane,the tear edge and dimple, which shows the characteristics of quasi-cleavage type brittle fracture. Compared with the state of as-cast, the fracture of composites in the state of T6heat treatment have more cleavage plane, less tear edge and dimple. CNTs disperse uniformly in the matrix and there is not obvious interface reaction between CNTs and ZL114matrix during the casting, and CNTs had a strong interface bonding with matrix.CNTs can significantly improve the wear resistance of composite, within a certain range, the friction coefficient and mass loss of the composite decreases with the increasing content of CNTs,wear mechanism of the composite consist of abrasive wear, oxidation and adhesive wear, abrasive wear are the mainly.After mixing3min, the dispersion of the composites is the best, the distribution density and amount of CNTs decreases gradually with stirring time increasing. The distribution density of CNTs is minimum when stirring lOmin, and it is almost difficult to observe CNTs in composites. A number of CNTs can be observed after standing5min and the amount of CNTs reduce drastically after standing7min.