Technology Description

The technology assessed in this report is an improved method for making aluminum composites that uses pressureless infiltration to form the end product. Generally speaking, aluminum composites are materials in which a reinforcement, typically a ceramic-based material, is added with the purpose of improving the material's properties. Of the variety of ceramic materials that can be used as reinforcements, silicon carbide (SiC) and aluminum oxide (Al2O3) are the two that have seen the greatest use as a result of their favorable combination of density, price, and property improvement potential .

Reinforcements also come in a number of forms: continuous fibers, whiskers, and particulates. When they are combined with an aluminum matrix, the resulting material has significant increases in stiffness, wear resistance, and, in some cases, strength and fatigue resistance. In addition, the coefficient of thermal expansion of aluminum is reduced by the addition of the reinforcement, while the material retains the high thermal conductivity and low density inherent in the aluminum alloy. These types of property changes, not generally possible through conventional alloying methods, have been the source of the excitement about aluminum composites.

The diagram below shows how pressureless infiltration works. This is from the website of TTC.

As can been seen, first the component is prepared in the desired shape. Second, aluminum alloy infiltration is accomplished by particle wetting at normal room pressure. Lastly, the part solidifies. The main drawbacks of pressure-assisted infiltration are the need for expensive tooling and the difficulty involved in making pressurized dies that support complex-shaped components.

Potential Benefits of The Technology

This technology has a number of advantages over most composites. First, it uses a much simpler process and is much more cost effective than pressurized systems. Second, the resulting composite is slightly stronger than other similar composites. Lastly, it can be used to produce a very thin end product with a uniform gradient.

Contact details:

Prof Vikram Jayaram,
Indian Institute of Science
Email: qjayaram@materials.iisc.ernet.in