Characterization of the copper rich phase precipitation behavior and comprehensive properties of austenitic stainless steel

Antibacterial austenitic stainless steel was nominated as a new biomaterial material. The copper rich phase precipitation behavior and comprehensive properties in copper-containing austenitic stainless steel after different aging treatment were systematically studied. It was found that a large number of dispersed copper rich phases developed at 750–800 °C. At 800 °C, copper rich phase precipitated quickly within 1 h, but grew and coarsened slowly in the later stage. The hardness of the material increased gradually with the precipitation of copper rich phase, until it reached the maximum after 6 h and tended to be stable. However, with the extension of aging time, high concentration of copper rich phase destroyed the passive film on the surface of stainless steel and accelerated the matrix corrosion, but promoted the release of copper ions and improved the antibacterial property. Therefore, the comprehensive experimental results indicated that 3.60% Cu-304L stainless steel treated by solid solution at 1050 °C for 5 min and aged at 800 °C for more than 6 h had good corrosion resistance and antibacterial property. These results could provide theoretical guidance for the optimal design of copper containing antibacterial stainless steel in production process.