Spinodal Decomposition Stabilizes Plastic Flow in a Nanocrystalline Cu-Ti Alloy

A combination of high strength and reasonable ductility has been achieved in a copper-1.7 at.%titanium alloy deformed by high-pressure torsion. Grain refinement and a spinodal microstructure provided a hardness of 254 ± 2 Hv, yield strength of 800 MPa and elongation of 10%. The spinodal structure persisted during isothermal ageing, further increasing the yield strength to 890MPa while retaining an elongation of 7%. This work demonstrates the potential for spinodal microstructures to overcome the difficulties in retaining ductility in ultra-fine grained or nanocrystalline alloys, especially upon post- deformation heating where strain softening normally results in brittle behavior.