电弧熔丝增材制造镍基合金性能与流动应力模型

Properties and flows stress model of nickel-based alloy by wire arc additive manufacturing

选用了一种镍基合金焊材(CHN327)用于新型“拳头式”锻模表面层的电弧熔丝增材制造,对模具镍基表层的显微组织、力学性能及该种镍基合金的中温流变行为进行了研究。对试样进行了10次以2℃/s的加热速度加热至700℃后淬火的处理,模拟了模具服役中的温度循环,并对加热和水淬前后的显微组织变化进行了表征。采用WDW-100万能试验机在温度600~700℃和应变速率0.001~0.1 s^-1范围内对镍基表层试样进行了单向中温拉伸试验,研究变形温度和应变速率对CHN327合金流变应力的影响,建立了镍基合金CHN327流变应力与变形条件之间关系的数学模型。结果表明:经加热-淬火温度循坏后,“拳头式”锻模镍基表面层γ″-Ni3Nb相含量增加,镍基表面层与铁基层的结合强度提高;镍基合金CHN327满足正应变速率敏感材料特性,基于Arrhenius模型拟合出的模型参数能较好地预测合金中温变形中的流动应力。

A surface enhanced layer was prepared on the die surface by wire arc additive manufacturing technology using nickel-based alloy(CHN327)as filler materials,and microstructure,properties and warm temperature flow behavior of the nickel-based alloy layer was studied.The specimen was quenched at 700℃for 10 times to simulate the temperature cycle in the service of the die,and the microstructure changes before and after heating and water quenching were characterized.One-way warm-temperature tensile tests of the nickel-based surface samples were carried out by using a WDW-100 universal testing machine in the temperature range of 600-700℃and strain rate of 0.001-0.1 s^-1,and the effects of deformation temperature and strain rate on flow stress of the CHN327 alloys were studied,a mathematical model was established for the relationship between flow stress and deformation conditions of the nickel-based alloys.The results show that theγ″-Ni3Nb phase content of the nickel-based surface layer and the bonding strength between nickel-based surface layer and iron-based layer are increased after ten cycles of heating and water quenching.The Ni-based alloy CHN327 meet the characteristics of normal strain rate sensitive materials.The model parameters based on the Arrhenius model can predict the flow stress in the warmtemperature deformation.