Microstructure and mechanical properties of Al–Si–Cu–Fe alloy-based ceramic particle-reinforced nanocomposites and microcomposites and a modified model to predict the yield strength of nanocomposites

Abstract

The effects of volume fraction, size, and type of reinforcement particles on the microstructure and mechanical properties of Al–Si–Cu–(Fe) alloy matrix composites were investigated and an analytical model was modified to predict the yield strength of the particle-reinforced nanocomposites. Nano- and micro-particle-reinforced Al–Si–Cu-(Fe) matrix composites (N-AMCs and M-AMCs) were manufactured by adding two different types and sizes of reinforcement particles to Al–Si–Cu–(Fe) alloys at different volume fractions using a two-step stir casting method combined with a high-energy ball milling process and a high-pressure die-casting method. Microstructural analyzes of N-AMCs and M-AMCs were performed using SEM, EDX, and XRD. The Brinell hardness test and the tensile test were carried out to determine the mechanical properties of the N-AMCs and M-AMCs. The hardness of the N-AMCs and M-AMCs was continuously enhanced by increasing the volume fraction of the reinforcement particles, while the yield strength and ultimate tensile strength of the N-AMCs and M-AMCs were improved up to 1.5 vol.% and 4 vol.% of nano-particles and micro-particles, respectively. An analytical model was modified to predict the yield strength of N-AMCs by integrating the effective volume ratio of nano-particles into each strengthening mechanism. The results predicted by the modified model reached nearly 98% agreement with the experimental results up to 1.5 vol.% of the reinforcement particles. Nano-particles had a much greater effect on strengthening mechanisms compared to micro-particles.

Analysis of Selected Production Parameters for the Quality of Pressure Castings as a Tool to Increase Competitiveness

“…These alloys have a low tendency to shrink and crack, which makes them suitable for producing thinwalled castings with complex shapes. However, their machinability is slightly worse than other aluminum alloys due to the presence of hard and abrasive silicon particles [21][22][23].…”

“…These alloy have a low tendency to shrink and crack, which makes them suitable for producing thin walled castings with complex shapes. However, their machinability is slightly worse tha other aluminum alloys due to the presence of hard and abrasive silicon particles [21][22][23] The selection of the appropriate aluminum alloy for casting depends on both desig and foundry properties. Design properties refer to the mechanical properties at standar low, or high temperatures and the density-strength ratio, corrosion resistance, weldabi ity, and machinability.…”

“…Figure 4 shows the measured values of ultimate tensile strength at constant plunger speed (4.5 m•s −1 ) in the filling chamber for the different levels of pressure or holding pressure in the mold cavity (22,28,and 32 MPa). As ultimate tensile strength is a key parameter for evaluating the mechanical properties of castings, the results provide important information on the effect of different process parameters on the mechanical strength of the castings.…”