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The alloy composition is an important factor effecting the pore structure of aluminum foam. In this paper, the powder compact foaming method was used, and different content of Cu element powders were added to the alloy Al–9Si, for investigating the effect of alloying element on foaming process. With the Cu content of Al–Si–Cu alloy increasing, the expansion ratio is increased, the time required to reach maximum expansion is shortened, and the number of fissure-like pores at early foaming stage is decreased. This improving action is related to the higher volume fraction of liquid phase in same melting temperature caused by increasing Cu content in alloy. Comparing different Al–Si–Cu alloys with different Cu content at same expansion ratio, the higher Cu content, the smaller pore size and the thinner cell wall. This beneficial effect on pore structure is attributed to the addition of Cu that is benefit to increasing the viscosity of Al–Si–Cu alloy during foaming. And at same expansion rate, the more content of Cu in Al–Si–Cu alloy, the higher compressive strength of aluminum foam.

Silicon/aluminum (Si/Al) composite is a kind of lightweight electronic packaging material that received a lot of attention in the past 20 years. In this paper, a series of Si/Al composites with lowered coefficient of thermal expansion (CTE) and high thermal conductivity were produced by powder metallurgy (PM). The Si/Al composites are fully dense and have fine Si particles uniquely distributed within pure Al matrix. Three 50%Si/Al composites were designed to have strength in the range of 185–290 MPa to meet different demands, while the other properties keep invariable. Fracture toughness of the composites is measured to be 9–10 MPa·m1/2. The composites were machined to 50%Si/Al housings and 27%Si/Al lids. Both the hermeticities of housings before and after laser-beam-welding sealing are determined. The measured leak rate of composites and sealed housings is in magnitude order of 1 × 10−10 and 1 × 10−9 Pa·m3·s−1, respectively, suggesting high hermeticity. The good hermeticity is attributed to the full dense materials, good weldability, and extremely low weld porosity. The present Si/Al composites are expected to be extensively used in highly hermetic electronic packages.

An analytical model was established to simulate the stress–strain curves of particle–reinforced metal matrix composites by the classical stress equilibrium equation and secant modulus method, where particle cracking and matrix tearing were taken into consideration. The stress–strain curves of the composites predicted by the model fit the experimental curves very well. The stress–strain relationship of the matrix affected by the particles is predicted exactly, and it is found that the yield stress of the matrix is influenced obviously by the particle content. The yield strength of the composites is also predicted by the model, and the results fit the experimental data very well.

15 vol% silicon carbide particle (SiCp)-reinforced 2009Al matrix (15 vol% SiCp/2009Al) composites were fabricated by hot isostatic pressing (HIP) and hot extrusion processes. The tensile and fracture properties of 15 vol% SiCp/2009Al were studied. The results showed that hot extrusion increased the ultimate tensile strength (UTS), yield strength (YS), elongation (EL), reduction in area (RA), and fracture toughness of the composites. The heat treatment resulted in the increase in UTS, YS, and fracture toughness, but a decrease in EL and RA. Both hot extrusion and heat treatment had negligible effects on elastic modulus (E). With the increase of SiCp size, the UTS, YS, and E decreased, but the EL and RA increased. The fracture toughness increased first and then decreased with increasing SiCp size, and when the SiCp size was about 7 μm, the composites obtained the maximum fracture toughness value of 31.74 MPa m1/2.