The invention relates to a contact with a gradient
fine grain structure and a preparation method and application thereof, and belongs to the field of
machine manufacturing. The method comprises the steps that a CuCr
alloy blank bar is subjected to finish
machining, a rolling
machining area is longitudinally reserved when the front face of the contact is machined, then the contact is put into a cryogenic low-temperature box to be subjected to low-temperature
nitrogen cryogenic treatment, an obtained contact blade is subjected to multiple times of rolling treatment to complete contact outer surface
machining, and the treated contact is put into a packaging bag to be sealed after being cleaned, deoiled and dried. According to the invention, gradient structure design is carried out on the contact, a CuCr material matrix-surface synergistic structure regulation and control method is developed under the condition that the existing structure is not changed, and the
vacuum arc-extinguishing chamber electrical contact with high
hardness and an ultra-
fine grain structure is developed. The
microstructure of the
alloy is controlled by adopting collaborative refining methods such as matrix
cryogenic treatment and surface rolling treatment, and reconstruction of the Cu-Cr two-phase
microstructure is achieved. The CuCr contact material and device with the grain size smaller than 10 microns and the
hardness improved by 30% under the condition of equivalent electric
conductivity are developed.