The role of MgO nanoparticles addition,and γ-irradiation on the microstructural,and tensile properties of Al-1100 alloy

Abstract

Aluminum matrix composites (AMCs) are innovative engineering materials in which a tough reinforcement is included in the aluminum matrix to improve its properties. In the study, MgO (0–4 wt.%) was loaded to Al-1100. The XRD reveals that MgO has a cubic crystal structure, purity of 100%, and the average crystallite size is 17.4 nm, from Scherer's formula. HR-TEM reflected that MgO displays nanoparticle-like morphology. The microstructural properties of AMCs manifested the intermetallic compounds’ absence, grain refinement, good MgO distribution, and the presence of few porosities. The density measurement confirmed the decrease in the experimental density with increasing MgO while the theoretical density increased. The maximum porosity found is 1.4% which is accepted in the fabrication of AMCs. The tensile properties revealed that as the strain rate ( $\dot{\epsilon }$ ), γ-irradiation dose, and MgO content increases, the fracture stress ( ${\sigma }_f$ ) increases while the ductility (ε_Τ) decreases. These three parameters could control the tensile properties of AMCs reinforced with MgO as well. An improvement by 140% in σ_f was achieved for AMC with 4 wt.% MgO (at $\dot{\epsilon }$  = 1.2 × 10⁻³ s⁻¹, 2 MGy) compared to plain Al-1100 alloy (at $\dot{\epsilon }$  = 5.4 × 10⁻⁵ s⁻¹, 0 Gy). It was suggested that the load transfer from matrix to reinforcement was efficient which directly improves the load-carrying ability of these synthesized AMCs. Several mechanisms such as Orowan strengthening, and dislocation strengthening, were suggested to interpret the tensile properties.