Latest research advances on magnesium and magnesium alloys worldwide

Micro structural characteristics and mechanical behaviour of aluminium matrix composites reinforced with titanium carbide

Aluminum becomes the most popular nonferrous metal and is widely used in many fields such as packaging, building transportation and electrical materials due to its rich resource, light weight, good mechanical properties, suitable corrosion resistance and excellent electrical conductivity. Grain refinement, which is obtained by changing the size of grain structure by different techniques, is a preferred method to improve simultaneously the strength and plasticity of metallic materials. Therefore, grain refining of aluminum is regarded as a key technique in aluminum processing industry. Up to now, there have been a number of techniques for aluminum grain refining. All the techniques can be classified as four categories as follows: grain refining by vibration and stirring during solidification, rapid solidification, the addition of grain refiner and severe plastic deformation. Each of them has its own merits and demerits as well as applicable conditions, and there are still some arguments in the understanding of the mechanisms of these techniques. In this article, the research progresses and challenges encountered in the present techniques and the future research issues and directions are summarized.

A Review on Grain Refinement of Aluminum Alloys: Progresses, Challenges and Prospects

Mo2C coating on diamond: Different effects on thermal conductivity of diamond/Al and diamond/Cu composites

Diamond particulates reinforced titanium matrix composites (TiMMCs) were fabricated by spark plasma sintering technique at different reinforcement sizes of 5, 100, 200 nm and 3 μm. The dependence of reinforcement size on the mechanical and tribological properties in the TiMMCs was studied, paying particular attention to the nanoscale effects. The enhancement in strength of the composites was elucidated on the basis of strengthening mechanisms characterized by load transfer, thermal mismatch, grain size, and Orowan strengthening. The strengthening mechanisms were quantitatively analyzed and evaluated as a function of particle size. The results revealed that the presence of 5 nm diamond particles enhance strength by interacting with dislocations, while simultaneously retarding grain growth. Although the micro-composite has a little higher strength than the nanodiamonds reinforced composite, the latter has a combination of high strength and high ductility as wells excellent tribological properties.

Reinforcement size dependence of mechanical properties and strengthening mechanisms in diamond reinforced titanium metal matrix composites

Diamond/Cu composites with high density and good thermal properties are fabricated by vacuum hot pressing via designing dual layers on the diamond particles. Different types of inner tungsten layers are coated on diamond after annealing with the loose tungsten powder, and the outer copper layer is then deposited using electroless plating. The effects of dual layers on the microstructure and thermal conductivities of diamond/Cu composite are investigated. The results indicate that the tungsten coating exhibits integrated and uniform structure when the diamond is treated with tungsten powder at 900 °C for 2 h. This tungsten coating improves the interfacial bonding and minimizes the thermal boundary resistance between the diamond and the copper matrix. Moreover, the outside copper coating promotes the sintering process, and hence favors the low-temperature densification of diamond/Cu composites. The thermal conductivity of diamond/Cu composites reaches 721 W m − 1  K − 1 , which is close to the theoretical value.

Effects of dual-layer coatings on microstructure and thermal conductivity of diamond/Cu composites prepared by vacuum hot pressing

Preparation of Al–Si alloys by a rapid solidification and powder metallurgy route

Effect of bimodal microstructure on the tensile properties of selective laser melt Al-Mg-Sc-Zr alloy

Microstructure and corrosion behavior of as-extruded Mg-xLi-3Al-2Zn-0.2Zr alloys (x = 5, 8, 11 wt.%)

Microstructure evolution and mechanical properties of an ultrahigh strength Al-Zn-Mg-Cu-Zr-Sc (7055) alloy processed by modified powder hot extrusion with post aging

Zhiyong Cai

Papers

Effects of dual-layer coatings on microstructure and thermal conductivity of diamond/Cu composites prepared by vacuum hot pressing

Preparation of Al–Si alloys by a rapid solidification and powder metallurgy route

Effect of bimodal microstructure on the tensile properties of selective laser melt Al-Mg-Sc-Zr alloy

Microstructure and corrosion behavior of as-extruded Mg-xLi-3Al-2Zn-0.2Zr alloys (x = 5, 8, 11 wt.%)

Microstructure evolution and mechanical properties of an ultrahigh strength Al-Zn-Mg-Cu-Zr-Sc (7055) alloy processed by modified powder hot extrusion with post aging