Enhancing Properties of Aerospace Alloy Elektron 21 Using Boron Carbide Nanoparticles as Reinforcement

Abstract

In this study, the effect of nano-B4C addition on the property profile of Elektron 21 (E21) alloys is investigated. E21 reinforced with different amounts of nano-size B4C particulates was synthesized using the disintegrated melt deposition technique followed by hot extrusion. Microstructural characterization of the developed E21-B4C composites revealed refined grains with the progressive addition of boron carbide nanoparticles. The evaluation of mechanical properties indicated a significant improvement in the yield strength of the nanocomposites under compressive loading. Further, the E21-2.5B4C nanocomposites exhibited the best damping characteristics, highest young’s modulus, and highest resistance to ignition, thus featuring all the characteristics of a material suitable for several aircraft applications besides the currently allowed seat frames. The superior mechanical properties of the E21-B4C nanocomposites are attributed to the refined grain sizes, uniform distribution of the nanoparticles, and the thermal insulating effects of nano-B4C particles.

Development from Alloys to Nanocomposite for an Enhanced Mechanical and Ignition Response in Magnesium

“…The reason for this is due to the formation of thermally unstable secondary phases; this indicates that the presence of thermally stable secondary phases is an important factor to improve ignition resistance. Previous studies on the ignition properties of magnesium-based nanocomposites have shown the enhancement of magnesium's ignition resistance due to the use of thermally stable reinforcements such as B 4 C, Sm 2 O 3 and CeO 2 nanoparticles [16,23,24]. In the current study, a further increase in ignition temperature from 692 • C in the Mg1Ca1Sc alloy to 752 • C in the Mg1Ca1Sc/B 4 C composite was observed (Figure 5).…”

“…In the case of the Mg1Ca1Sc/B 4 C composite, the particle reinforcement caused a 58% reduction in grain size in relation to the Mg1Ca1Sc alloy, and 92% reduction in relation to Mg. This clearly shows that the fine B 4 C particulates had a strong capability in grain growth restriction through the classical grain-boundary pinning mechanism [15,16]. In addition, the homogeneous grain-distribution pattern was attained (Figure 4d) as a consequence of microstructural homogeneity, in terms of good second phase distribution in the composite (Figures 1c and 2c).…”

“…Among the commercial Mg alloys, the Elektron 21 (E21) alloy met the requirements and passed the flammability test from the Federal Aviation Administration (FAA). It is highly qualified to be used in the aviation industry [16]. E21 is composed of high-density alloying elements such as Neodymium, Gadolinium, Zinc and Zirconium; its density is similar to the density of the AZ series Mg alloys (~1.8 g/cm 3 ).…”

“…Finally, B 4 C nanoparticle reinforcement was added into the Mg1Ca1Sc alloy to develop the Mg alloy composite. The selection of B 4 C for the reinforcement phase was based on previous studies [15,16] which have reported the advantages of using this reinforcement phase in improving the mechanical and ignition properties of Mg and Mg alloys.…”