# The Influence of Process Conditions and Reinforcement Characteristics on the Densification and Mechanical Properties of Powder Metallurgy SiCp/Al Composites

## TL;DR

This study improves the production of aluminum composites by optimizing process conditions and material composition for better strength and density.

## Contribution

A novel approach combining pure aluminum powder with 2024 aluminum alloy and SiC to enhance powder compaction and mechanical properties.

## Key findings

- Sintering at 600 °C for 30 min yields optimal interparticle bonding without precipitate or pore coarsening.
- Hot pressing increases tensile strength by over 70% compared to sintering alone, reaching 343 MPa.
- Higher SiC content and particle size in the hot-pressed state reduce mechanical performance.

## Abstract

Compared to pure aluminum powder, aluminum alloy powders exhibit higher strength and hardness, which leads to greater difficulty in plastic deformation during cold compaction, consequently impairing green compact formation and subsequent densification. This study introduces pure aluminum powder into the raw material system based on 2024 aluminum alloy powder and SiC powder, effectively improving the powder compaction characteristics. A systematic investigation was conducted to examine the effects of sintering temperature (460–640 °C) and holding time (5–120 min) during pressureless sintering on the sintering shrinkage, relative density, mechanical properties, and microstructure of SiCp/Al composites reinforced with 35 wt.% of 31.9 μm SiC particles. The results indicate that sintering at 600 °C for 30 min constitutes the optimal process condition, achieving effective interparticle bonding while preventing coarsening of both precipitates and pores. Subsequent hot pressing effectively enhanced the relative density and mechanical properties of the sintered preforms, achieving a maximum tensile strength of 343 MPa, which represents an improvement of over 70% compared to the sintered-only state. For the hot-pressed state, elevated levels of SiC particle content and size compromised its mechanical performance. This work demonstrates a highly operable and industrially viable processing route for manufacturing aluminum matrix composites using alloy powders.