Self-Lubricating Property of TiB2-Ni Coating in the Hot Forging Die of Aluminum Alloy

Hot die forging is a forging forming method widely used in the automobile industry, shipbuilding, and the aerospace industry. In the hot die forging process of aluminum alloy, the “mold sticking” defect often occurs and results in low productivity and short die life. Herein, we prepared TiB2 reinforced nickel-based coatings by the combined use of a plasma transferred arc and plasma melt injection method, and investigated the morphology and properties of composite coatings in hot forging die conditions. The results showed that the nickel-based coating reinforced with TiB2 generated boron-rich self-lubricating products during the sliding with aluminum alloy, and the adhered aluminum alloy on a coating surface has significantly reduced quantity and transformed morphology from rough plough to smooth layer with the increase of TiB2, which is beneficial to the surface quality of the aluminum alloy counterface. The results of this research provide valuable guidelines for the design and preparation of the coatings applied in the mold in hot die forging of aluminum alloys.