Effect of Magnesium on Microstructure Refinements and Properties Enhancements in High-Strength CuNiSi Alloys

• 来源期刊: 金属学报（英文版）
• 年，卷（期）: 2020,（3）
• 页码范围: 375-384
• 页数: 10页
• 语种: 英文

摘要

Microalloying is an effective method to improve the comprehensive properties of copper alloys.The effects of magnesium on the microstructure,mechanical properties and anti-stress relaxation properties of CuNiSi alloys have been investigated.Results demonstrated that magnesium plays significant roles in refining the dendritic microstructure of the as-cast ingot,accelerating the precipitation decomposition,improving the mechanical properties and increasing the anti-stress relaxation properties.The incremental strength increase is due to the Orowan strengthening from the nanoscale Ni2Si and Ni3Al precipitates.As compared with the Cu-6.0Ni-1.0Si-0.5Al (wt％) alloy,the ultimate tensile strength of the designed Cu-6.0Ni-1.0Si-0.5Al-0.15Mg (wt％) alloy increases from 983.9 to 1095.7 MPa,and the electrical conductivity decreases from 27.1 to 26.6％ IACS,respectively.The stress relaxation rates of the designed Cu-6.0Ni-1.0Si-0.5Al-0.15Mg alloy are 4.05％ at 25 ℃,6.62％ at 100 ℃ and 9.74％ at 200 ℃ after having been loaded for 100 h,respectively.Magnesium significantly promotes nucleation during precipitation and maintains small precipitate size.