铜合金模具材料电子束选区熔化成形件耐磨性及机理分析

Wear Resistance and Mechanism Analysis of Copper Alloy Die Material Forming Parts By Electron Beam Selective Melting

采用电子束选区熔化成形技术在316L不锈钢基板上成形CuAl0Fe3铜合金块体试样,分析了合金试样的物相组织,微观组织、显微硬度和摩擦磨损性能,揭示了EBSM铜合金的磨损机制和耐磨机理。结果表明,EBSM铜合金成形件的物相结构为fcc结构的基体塑性α相+交替片成(α+γ_2)共析相+纳米级弥散分布的K相;截面微观组织为尺寸在30～45μm的等轴胞状晶;由于金属增材制造电子束快冷条件而引起的细晶强化、硬脆相和富铁K相的弥散强化,使得EBSM成形件的平均显微硬度达到215HV,是锻造合金的1.3倍;同时EBSM件在相同干摩擦条件下摩擦系数和磨损体积均小于锻件,耐磨性较锻件提高了1.23倍。磨痕形貌观察,EBSM件的磨损机制主要为磨粒磨损,同时伴随着有粘着磨损、疲劳磨损和氧化磨损。

The CuAlOFe3 copper alloy samples were formed on 316L stainless steel substrates by electron beam selective melting.The phase structure,microstructure,microhardness and friction and wear properties of the copper alloy samples were analyzed.The wear mechanism and wear resistance mechanism of EBSM copper alloy were revealed.The results show that the phase structure of EBSM copper alloy parts is matrix plasticity a phase+alternating sheet(α+γ2)eutectoid phase+nano-dispersed K phase;the cross-section microstructure is equiaxed cellular crystals with the size of 30-45μm;due to fine grain strengthening,hard brittle phase and diffusion strengthening of iron-rich K phase caused by rapid cooling of electron beam produced,the average microhardness of the EBSM copper alloy reaches 215 HV,which is 1.3 times of the forging.At the same time,the friction coefficient and wear volume of EBSM parts under the same dry friction condition are less than the forging,and the wear resistance of EBSM parts is 1.23 times higher than that of forging.The wear mechanism of EBSM parts is mainly abrasive wear,accompanied by adhesive wear,fatigue wear and oxidation wear.