Elevated Temperatures Tensile Characteristics of Cast A356/Al<sub>2</sub>O<sub>3</sub> Nanocomposites Fabricated Using a Combination of Rheocasting and Squeeze Casting Techniques

Abstract

In the present investigation, the tensile properties of A356/Al 2 O 3 nanocomposites at both ambient and elevated temperatures were studied. The A356/Al 2 O 3 nanocomposites were fabricated using a combination between the rheocasting and squeeze casting techniques. The A356 matrix alloy was reinforced with Al 2 O 3 nanoparticulates having average sizes of 60 nm and 200 nm with different volume fractions up to 5 vol%. The results revealed that the A356/Al 2 O 3 nanocomposites exhibited better mechanical properties than the A356 monolithic alloy. Such improvement in the mechanical properties was observed at both room and elevated temperatures up to 300˚C. Increasing the volume fraction and/or reducing the size of Al 2 O 3 nanoparticulates increase both the tensile and yield strengths of the nanocomposites.

Dynamic Behaviour of Cast A356/Al<sub>2</sub>O<sub>3</sub> Aluminum Metal Matrix Nanocomposites

“…These results show that the natural frequency of composites having small particulates size (60 nm) more than that of larger particulates size (200 nm). These results due to the decrease of particulates size were increasing both composites strength and ductility as concluded in the previous work conducted by El-Kady et al [9], hence increasing stiffness and natural frequency. Similar results were obtained when calculating the storage modulus, loss factor and loss modulus, where these parameters were strongly affected by increasing volume fraction or decreasing particulates size as discussed before where the effects were subject to the same reasons which effects on damping factor and natural frequency.…”

“…Nowadays, interest is growing in producing composites reinforced by nanoparticulates either by adding these particulates to liquid metals or by in situ techniques. Many researches [8,9] have claimed enhanced properties for the produced composites relative to those produced by reinforcing with the micro-particles. Few investigations were reported on the dynamic properties of metal matrix nanocomposites (MMNCs).…”

Microstructure and Mechanical Properties of MWCNTs Reinforced A356 Aluminum Alloys Cast Nanocomposites Fabricated by Using a Combination of Rheocasting and Squeeze Casting Techniques

“…The microstructural changes are attributed to both the stirring action carried out during the addition of the MWCNTs and the heterogeneous nucleation performed by the MWCNTs themselves. The effectiveness of squeezing is to break up agglomerates, help the redistribution of MWCNTs, and improve the microstructure [21]. Figure 11 illustrates the influence of the addition of MWCNTs with different weight fractions on the Rockwell B hardness of A356 alloy.…”

High-temperature mechanical properties of cast Al–Si–Cu–Mg alloy by combined additions of cerium and zirconium

“…In order to improve the mechanical properties of aluminum alloys, strategies involving minor additions of transition metals like zirconium [6], rare-earth metals, such as cerium [7][8][9], lithium [10], Al 3 O 2 nanocomposites [11] and Al-Mg 2 Si in situ composites [12] can be cited. In recent years, efforts have been made for improving cast alloys mechanical properties, mainly in superior temperatures than the ones of the conventional applications.…”