Mechanical damping characteristics of ductile and grey irons micro-alloyed with combinations of mo, ni, cu and cr

Damping behaviour of ductile and grey cast irons micro alloyed with combinations of Mo, Ni, Cu and Cr, was investigated in this study. This was aimed at establishing the effect of composition and microstructural parameters on the damping properties of the micro alloyed cast irons. Grey cast iron was micro alloyed randomly with molybdenum, nickel, chromium and copper at an amount not more than 0.2 % each; magnesium was added to the melt in ladle prior to casting. The microstructures showed that ductile iron was formed and grey iron was also formed due to insufficient ‘nodulizer’, the ductile iron consisted of pearlite and ferrite phases with their nodular graphite. The micro-alloyed ductile iron generally had higher storage (78906 – 120868 MPa) and loss modulus (5375 – 6715 MPa) than that of the grey cast iron and ductile iron composition without alloying elements. Although the damping capacity of the composition without micro alloying elements was initially higher for all the cast irons (~ 0.085), but failed at approximately 110 ᵒC, while most of the micro-alloyed ductile irons exhibited relatively satisfactory capacity for vibration energy dissipation up to 190 ᵒC than the micro-alloyed grey irons.