The heat treatment effect on microstructure and dynamic mechanical properties of electroformed nanocrystalline Ni-W alloy

Ni-W alloys coatings with minimum residual stress can be electrodeposited by using electrodepositing bath with additive saccharin at similar to 2.5 g/L. Grain size of electroformed Ni-36.4 wt% W heat-treated at below 400 degrees C grew slowly with heat treatment temperature rising. However, it grew quickly as heat treatment temperature increased from 400 degrees C to 500 degrees C. The dynamic strength of electroformed Ni-36.4 wt% W alloy after heat treatment increases but the dynamic ductility decreases with strain rate increasing in the range of 2800-5400s(-1). At the strain rate 2800s(-1), the best dynamic strength and ductility of Ni-36.4 wt% W alloy can be obtained by heat treatment at 300 degrees C comparing with that as-deposited and heat treatment at 200-500 degrees C. (C) 2012 Elsevier B.V. All rights reserved.