Dry Wear Behaviour of the New ZK60/AlN/SiC Particle Reinforced Composites.

This study deals with the microstructure, mechanical, and wear properties of the extruded ZK60 matrix composites strengthened with 45 µm, 15% silicon carbide particle (SiC) and 760 nm, 0.2-0.5% aluminium nitride (AlN) nanoparticle reinforcements. First, the reinforcement elements of the composites, SiC and AlN mixtures were prepared in master-magnesium powder, and compacts were formed under 450 MPa pressure and then sintered. Second, the compacted reinforcing elements were placed into the ZK60 alloy matrix at the semi-solid melt temperature, and the melt was mixed by mechanical mixing. After the melts were mixed for 30 min and a homogeneous mixture was formed, the mixtures were poured into metal moulds and composite samples were obtained. After being homogenized for 24 h at 400 °C, the alloys were extruded with a 16:1 deformation ratio at 310 °C and a ram speed of 0.3 mm/s to create final composite samples. After microstructure characterization and hardness analysis, the dry friction behavior of all composite samples was investigated. Depending on the percentage ratios of SIC and AlN reinforcement elements in the matrix, it was seen that the compressive strength and hardness of the composites increased, and the friction coefficient decreased. While the wear rate of the unreinforced ZK60 alloy was 3.89 × 10-5 g/m, this value decreased by 26.2 percent to 2.87 × 10-5 g/m in the 0.5% AlN + 15% SiC reinforced ZK 60 alloy.

Microstructural, mechanical, and in vitro corrosion properties of biodegradable Mg-Ag alloys.

In this study, casting, extrusion, biocorrosion, and corrosive wear properties of 0.5 wt. % (Zn, Ca, and Nd) element added Mg-3 wt. % Ag alloys were investigated. According to the test results, it was observed that the grain refinement occurred with the effect of Zn and Ca element additions in the as-cast alloys and thus some mechanical properties of the alloys improved. Similarly, the extrusion process provided grain refinement and improved mechanical properties. As a result of in vitro corrosion tests, similar results were also obtained in the as-cast alloys, while this situation became more apparent in the extruded alloys and exhibited more homogeneous corrosion properties. In the corrosive wear tests, the wear rate of the extruded alloys generally showed a decreasing trend. However, both the as-cast and extruded Mg-3 wt. %Ag-0.5 wt. % Ca alloys exhibited the lowest wear rate.