Stiffness and Vibration Damping Capacity of High Strength Cast Irons

The trend to lightweight design of automotive engines has led to the development of new cast iron grades for cylinder blocks, with very high fatigue properties, resulting in engines in some cases even lighter than engines with cylinder blocks of aluminum. On the other hand, the selection of cast irons grades with high values of mechanical strength and high elastic modulus, for projects of thin-wall engine blocks, may result in decrease in vibration damping capacity, even still far superior to aluminum cylinder blocks. This paper deals with damping capacity and elastic modulus of high strength cast irons, considering how the microstructure affects these properties and how to optimize them.