Study of the Effect of the A206/1.0 wt. % γAl2O3 Nanocomposites Content on the Portevin-Le Chatelier Phenomenon in Al/0.5 wt. % Mg Alloys

Abstract

The Portevin-Le Chatelier (PLC) phenomenon or dynamic strain aging in Al–0.5 wt. % Mg alloys was investigated at different strain rates. This research also examined the effect of γAl2O3 nanoparticles on the PLC phenomenon. A nanocomposite made of A206/1.0 wt. % γAl2O3 was manufactured to this purpose and then, added to an Al–0.5 wt. % Mg melt to obtain ingots of Al–0.5 wt. % Mg–20 wt. % A206/1.0 wt. % γAl2O3 and Al–0.5 wt. % Mg–10 wt. % A206/1.0 wt. % γAl2O3 with 6 mm diameter. Cold deformation allowed manufacturing 1 mm diameter wires using the 6 mm diameter ingots. A 300 °C solution treatment, followed by rapid cooling in ice water permitted to retain Mg atoms in solid solution. The tensile tests performed on the wires revealed the PLC phenomenon upon the tensile stress vs. strain plastic zone. The phenomenon was quantified using MatLab™ and statistical analysis. The results demonstrated how the alumina nanoparticles can diminish the serration amplitude of the PLC phenomenon.

Influence of Heat Treatment and Reinforcements on Tensile Characteristics of Aluminium AA 5083/Silicon Carbide/Fly Ash Composites

“…From the graph, it is evident that the % elongation of the composites decreases with the increase in the wt.% of SiC and fly ash and the heat treatment temperature, mainly attributed to the coherent bonding and interstitial micro coring and increase in the stiffness of the material. This is also supported by the inferences of Florián-Algarín et al [44], who concluded that, as the strength increases, the elongation decreases; this is due to the fact that the increase in strength, especially the increase in ultimate tensile strength, yields in increased strength, and Young's modulus significantly increases the stiffness of the material, thereby decreasing the tenacity related to the % elongation (ductility). However, at the thermal exposure temperature of 160 • C, there is a slight increase in the % elongation, due to the critical softening of the material occurring consequent to the thermal deformation, beyond which the % elongation decreases due to embrittlement accelerated by the strain hardening, as noted in the works of Lu et al [45] on the influence of hard ceramic reinforcements in enhancing the mechanical strength of the composite materials.…”

“…From the graph, it is evident that the % elongation of the composites decreases with the increase in the wt.% of SiC and fly ash and the heat treatment temperature, mainly attributed to the coherent bonding and interstitial micro coring and increase in the stiffness of the material. This is also supported by the inferences of Florián-Algarín et al [44], who concluded that, as the strength increases, the elongation decreases; this is due to the fact that the increase in strength, especially the increase in ultimate tensile strength, yields in increased % Elongation % Elongation is an important attribute for determining the ductility of the composites; specifically, it gives an overview of the length up to which the material elongates in the plastic zone before fracturing. The bar chart in Figure 17 lists the % elongation that the composites undergo before failure.…”

Multi-Objective Optimization of Novel Aluminum Welding Fillers Reinforced with Niobium Diboride Nanoparticles

“…Figure 2 shows the filler manufacturing steps, i.e., NbB 2 particle manufacturing, stir casting, and quality testing. Before manufacturing the proposed experimental filler, NbB2 particles must be prepared and embedded into an aluminum matrix through cold welding [6,10,[13][14][15][16]. Stir casting then further improves the bonding of the reinforcing particles due to melt agitation [21].…”

“…The rotational speed was set at 1020 rpm for 1 h, with a BPR of 10:1 [24] (Figure 2c). After cold welding, we sintered the pellets to enhance the aluminum/diboride interface to reduce porosity [6,10,[13][14][15][16]. A 200 °C annealing for 30 min in a reduced vacuum atmosphere (4 kPa) permitted the enhancement of the aluminum/diboride interface by removing residual stresses in the Al/NbB2 composite produced during the intense plastic deformation To ensure proper particle dispersion during pellet fabrication, we used a hot plate stirrer to mix an isopropanol solution with the NbB2 and pure Al powder, with an Al-to-NbB2 mass ratio of 90:10 (Figure 2b).…”

“…Furthermore, incorporating nanoparticles has raised a given metal's mechanical strength [10][11][12]. For instance, the addition of niobium diboride (NbB 2 ) nanoparticles strengthens a pure aluminum matrix used in wire fabrication [6,[13][14][15][16], showing improvements in strength, oxidation resistance, operating temperature, stiffness, wear resistance, and increasing the electrical conductivity [2,6,15,17].…”