Microstructure and Performance of a Three-Layered Al/7075–B4C/Al Composite Prepared by Semi Continuous Casting and Hot Rolling

Abstract

A three-layered composite material, consisting of an Al outer layer and a 7075-10 wt % B4C inner layer, was fabricated by semi-continuous casting and following a hot rolling process. The composite exhibits a clear layered structure with a good interfacial bond between layers. In the sessile drop experiment, the Al alloy melt dropped on the 7075-B4C composite at 650 °C, with the contact angle decreasing from 105° to 25° in 50 s, indicating that the infiltration and spreading both played important roles in the wetting process. In the inner layer, the reinforced B4C particles were distributed uniformly in the 7075 alloy matrix, and enhanced the average hardness of the inner layer to 163.4 HV, compared to that of the outer layer at 32.8 HV. The composite plate of 20 mm obtained the compression strength of 152 MPa. The electron probe microanalysis (EPMA) line scanning result showed that no harmful reaction or element diffusion occurred between B4C and the surrounding 7075 matrix. The B4C particles remained mechanically bonded into the matrix, and significantly reduced the bullet speed during the projectile impact test.

Influence of Interface on Mechanical Behavior of Al-B4C/Al Laminated Composites under Quasi-Static and Impact Loading

“…The interface between the different layers is clear and visible from a macro perspective of the Al-B 4 C/Al laminated composites section shown in Figure 2 (based on the distinct darkness difference between 6061Al and 15 vol.% B 4 C/6061Al). However, the interface between the B 4 C/Al layer and Al layer is not integrated nor continuous from a micro perspective in Figure 5b, which exhibits an alternative arrangement of the B 4 C particles and Al matrix [23,27,31]. The interface morphology is different from the same straight and continuous interfaces of the metal laminated composites [1,9,11,14].…”

“…Chao et al studied the ballistic performance of B 4 C/AA2024 functionally graded composites with wide range B 4 C volume fraction, and found that crack deflection appears in the interface of the top and middle layer [20]. A three-layered Al/7075-B 4 C/Al composite was prepared by semi continuous casting and hot rolling, significantly reducing the bullet speed during the projectile impact test [27]. It is necessary to do the basic research on the properties and mechanism of laminated PRMMCs under different loading to support more application research.…”

Contact and Infiltration Behavior of Al Melt and Al-B4C Composite

“…e metal-cermet three-layered composite combines the advantages of both metal matrix composites and the three-layered composite materials [5,6]. It is an ideal material in the areas of light protection and bulletproof armor for which ballistic performance is an important index.…”