Yang Wang,Qiang Liu,Biao Zhang,Haoqian Zhang,Zhaoxin Zhong,Jian Ye,Yuhan Ren,Liying Shen,Feng Ye,Wen Wang
Inspired by nacreous architecture, the 2024Al/20–50 vol% B 4 C composites with a lamellar-interpenetrated structure were successfully manufactured via freeze casting and pressure infiltration, and the quasi-static and dynamic characteristics were conducted at strain rates ranging from 0.001 to 3000 s −1 . The strength of the composites enhanced as the strain rate increased up to 2000 s −1 since the strain rate hardening effect facilitated the accumulation of dislocations. At the strain rate of 3000 s −1 , the adiabatic shear banding and its induced cracking were formed as the strengthening mechanisms were overcome by the thermal softening, which converted the dislocation structure from dislocation clusters to recrystallized grains, accompanied by a decrease in dislocation density, thereby degrading the compressive strength . A rigid network structure was formed in the composites with high particle content, and each particle had more inter-particle contact points, which made the strength of the composites increase with the increase of particle reinforcement content. This was also the reason why the strain rate sensitivity of the composites was considerably raised by introducing more particle reinforcement . However, increasing particle content heightened the composite susceptibility to strain localization and adiabatic shear damage, resulting in more brittleness of the 2024Al/50 vol% B 4 C composite at high strain rates . These findings could deepen the comprehension of the mechanical response and damage evolution of nacre-like composites exposed to extreme conditions and promote their applications.
Chuandong Wu,Pan Fang,Guoqiang Luo,Fei Chen,Qiang Shen,Lianmeng Zhang,Enrique J. Lavernia
We report on a study on the influence of Plasma activated sintering (PAS) parameters on the microstructure and mechanical properties of aluminum matrix composites (AMCs). In this paper a commercial Al alloy (7075) reinforced with 7.5 wt.% B 4 C were synthesized using PAS. Specifically, we studied the influence of temperature, in the range of 450 °C to 540 °C, and holding time on the densification behavior of Al-7075/B 4 C composites. Moreover, the influence of residual porosity on mechanical properties of Al-7075/B 4 C composites was established via measurements of Vickers hardness, bending and compressive strength. High mechanical properties including Vickers hardness 181.6 HV, bending strength 1100.3 MPa, high compression yield strength 878.0 MPa and fracture strength 469.3 MPa of the consolidated Al-7075/B 4 C composite sintered at 530 °C for 3 min were achieved and attributed to a fully dense microstructure and a strong interface between matrix and reinforcement.
危险品化学品经营许可证（带存储）