Aluminum and magnesium alloys are gaining more recognition for light-weight materials applications. In spite of this, such alloys have not been used for critical mechanical applications mainly due to their inferior mechanical properties compared to other engineering materials such as steel. Hence, many researchers have attempted to reinforce these alloys and obtain light-weight materials with excellent mechanical properties. The reinforcement process of the alloy can be achieved by introducing another material to form metal matrix composites. Different studies show that such composites exhibit improved properties, such as increased yield strength and tensile strength, enhanced stiffness, improved thermochemical properties, etc. However, the introduction of nanomaterials into the metal matrix is rather difficult due to the harsh manufacturing conditions employed for processing the metal composites.
The group of Prof. Reshef Tenne has developed state-of-the-art aluminum- and magnesium-based metal matrix composites, comprising small amounts of inorganic nanomaterials, such as nanotubes and spherical nanoparticles. The new nanocomposites exhibit much superior mechanical properties compared to the pristine alloy.
· Automotive, transportation, and aerospace industries
· Jet engine technologies
· Medical technologies
· Light-weight metal alloys
· Excellent mechanical properties
· Straight-forward fabrication technique
Aluminum (AA6061) and magnesium (AZ31) alloys were combined with small amounts (up to 1 wt.%) of either tungsten disulfide nanotubes or inorganic fullerene-like tungsten disulfide nanoparticles to form metal matrix composites using a melt-stirring reactor operated at high temperatures (up to 750oC). These nano-structures exhibit unique mechanical properties, which make their usage as composite fillers very promising, and a remarkable stability at elevated processing temperatures. Despite the small amounts of added nanostructures, their addition led to notable improvements in the mechanical properties of the alloys. Surprisingly, both the tensile strength of the alloys and their elongation (and consequently the fracture toughness) were improved by 10-20%. Depending on the nano-structure type and concentration, the hardness, yielding strength, ultimate tensile strength, and ductility were improved by up to ~70%. Physical considerations suggest that the main mechanism responsible for the reinforcement effect lies in the mismatch between the thermal expansion coefficients of the metal and the nano-structures.