High-Temperature Compressive Response of SiCp/6092Al Composites under a Wide Range of Strain Rates

Abstract

The high-temperature dynamic compressive properties of a 30 vol.% SiCp/6092Al composite, fabricated using powder metallurgy, were experimentally investigated using the split Hopkinson pressure bar system with an electric furnace. Three different ambient temperatures, namely, room temperature, 200 °C, and 350 °C, were adopted, and the dynamic tests of the composite specimens were conducted at strain rates ranging from 1500 to 4500 s−1. The experimental results showed that the flow stress of the composite was generally insensitive to strain rates at room temperature. However, the composite started exhibiting different strain-rate-dependent behaviors as the temperature increased, and the flow stress nonlinearly varied with increasing temperature. In addition, the microscopic images of the specimens showed that the microscopic failure mechanisms of the composite were greatly influenced by the ambient temperature and strain rate. Specifically, the percentage of failed particles decreased with rising temperature and the dominating failure mode of particles changed significantly as the strain rate increased.

A Review of Dynamic Mechanical Behavior and the Constitutive Models of Aluminum Matrix Composites

“…Additionally, under dynamic compression, the Al matrix partially melted due to adiabatic heating, leading to increased deformation of the matrix, which effectively inhibited crack propagation and increased the strain. Suo et al [46] studied the dynamic compressive mechanical properties of SiC/6092Al at different temperatures. As shown in the Figure 6 [46], their findings revealed notable strain rate hardening at room temperature, showing an escalation in flow stress and yield strength as the strain rate increased.…”

“…Suo et al [46] studied the dynamic compressive mechanical properties of SiC/6092Al at different temperatures. As shown in the Figure 6 [46], their findings revealed notable strain rate hardening at room temperature, showing an escalation in flow stress and yield strength as the strain rate increased. However, when the temperature reached 350 • C, the material experienced strain rate softening.…”

“…In addition, temperature also has a significant influence on the strain rate sensitivity of materials. Suo et al [46] investigated the high-temperature dynamic compressive performance of powder metallurgy-manufactured 30 vol.% SiC/6092Al composites under three different environmental temperatures and strain rates. The experimental results indicate that, at room temperature, the flow stress of the composites is essentially insensitive to the strain rate.…”

“…Existing studies indicate that damage to the reinforcement and interfacial debonding during dynamic loading can lead to the strain softening of AMMCs [43,44]. Additionally, the softening of the aluminum matrix at high strain rates or temperatures, as well as the formation of adiabatic shear bands, can counteract the work-hardening effect, reducing the flow stress level of the composite material and causing strain softening [46]. This work will review the strain softening of composites from the perspectives of the cracking of reinforcement particles and matrix softening.…”