Baolin Wu

Exploration of Al-based matrix composites reinforced by hierarchically spherical agents

Al-based composites reinforced with Al-Ti intermetallic compounds/Ti metal hierarchically spherical agents were successfully fabricated by powder metallurgy. This kind of structure produces strongly bonded interfaces as well as soft/hard/soft transition regions between the matrix and reinforced agents, which are beneficial to load transfer during deformation. As expected, the resultant composites exhibit promising mechanical properties at ambient temperature. The underlying mechanism was also discussed in this paper.

Enhanced compression ductility of stoichiometric NiAl at room temperature by Y and Cu co-addition

The combined effects of (Y, Cu) on the microstructure and room-temperature mechanical properties of the NiAl intermetallic compound under uniaxial compression stress were investigated. It is found that the co-addition of Y and Cu enlarges the difference between the intergranular yield strength and the intragranular yield strength of NiAl grains. Hence, for the resultant NiAl-(Y,Cu) alloy, a mechanically hierarchical structure forms. This is beneficial to improve the room-temperature mechanical response of NiAl alloys; as a result, the resultant alloy with 0.56at% (Y, Cu) exhibits a remarkably enhanced compression plasticity of about 11.2%.

Microstructure and mechanical properties of Al–5.5Fe–1.1V–0.6Si alloy solidified under near-rapid cooling and with Ce addition

Al–Fe–V–Si alloys were developed for use at elevated temperature and usually produced through a rapid solidification–powder metallurgy route. In this work, effort was made to produce the material via casting route. The studied alloys were cast under the condition of near-rapid cooling. The influence of Ce addition on microstructure and mechanical properties of near-rapid solidified alloys were investigated. The results indicate that the as-cast microstructure of Al–5.5Fe–1.1V–0.6Si alloy is significantly refined when the alloy was solidified under near-rapid cooling. Adding Ce results in the further refinement of intermetallic compound and the formation of an Al–V–Ce phase which replaces the primary phase Al13(Fe,V)3Si. The mechanical properties of the alloy are significantly improved by Ce addition: More than 70% increase in tensile strength and elongation is achieved by adding 1.00xa0wt% Ce to the alloy. It is concluded that near-rapid cooling and Ce addition are effective in improving mechanical properties of cast Al–5.5Fe–1.1V–0.6Si alloy.

Microstructure and mechanical properties of a hot-extruded Al-based composite reinforced with core–shell-structured Ti/Al3Ti

An Al-based composite reinforced with core–shell-structured Ti/Al3Ti was fabricated through a powder metallurgy route followed by hot extrusion and was found to exhibit promising mechanical properties. The ultimate tensile strength and elongation of the composite sintered at 620°C for 5 h and extruded at a mass ratio of 12.75:1 reached 304 MPa and 14%, respectively, and its compressive deformation reached 60%. The promising mechanical properties are due to the core–shell-structured reinforcement, which is mainly composed of Al3Ti and Ti and is bonded strongly with the Al matrix, and to the reduced crack sensitivity of Al3Ti. The refined grains after hot extrusion also contribute to the mechanical properties of this composite. The mechanical properties might be further improved through regulating the relative thickness of Al–Ti intermetallics and Ti metal layers by adjusting the sintering time and the subsequent extrusion process.