Metal matrix composites (MMCs) are materials made by combining a metal alloy with another material to give it specific properties, such as low weight, high strength, and high stiffness. One type of MMC is particulate reinforced MMC, made of small particles of the reinforcement material mixed into the metal alloy. However, these MMCs can have problems with an uneven distribution of particles, low ductility, and poor toughness and resistance to cracks. To improve these properties, shape memory alloys (SMAs) can be used as the reinforcement. SMAs are materials that can change shape in response to certain conditions and have been added to metal or polymer matrices to improve their mechanical properties. In this study, researchers looked at how NiTi particles, a type of SMA, behave when mixed into a particular type of aluminum alloy and how the microstructure and heat treatment of the aluminum alloy affects the NiTi particles. They found that the NiTi particles improve the precipitation and damping properties of the aluminum alloy and that the transformation of the NiTi particles is affected by the heat treatment, the vibration frequency, and the cooling/heating rate. The presence of aluminum in the NiTi particles also affects the transformation, but it does not have a clear effect on the temperature at which the transformation occurs. This research could have applications in the design and development of MMCs with improved properties.
R.R. Thorat et al. “On the transformation behaviour of NiTi particulate reinforced AA2124 composites”.
In: Journal of Alloys and Compounds 477.1-2 (2009), pp. 307–315. doi: 10.1016/j.jallcom.2008.11.002.