中间合金粉对激光选区熔化TMZF合金电化学性能的影响

Effects of Master Alloy Powders on Electrochemical Performance of Selective Laser Melted TMZF Alloy

为了探究激光选区熔化(Selective laser melting,SLM)Ti-12Mo-6Zr-2Fe(TMZF)β钛合金的腐蚀电化学行为,采用纯Mo粉末和Mo-Fe中间合金合金粉两种不同的Mo元素添加形式分别组成混合粉末进行激光增材制造,研究了中间合金粉末对TMZF合金试样组织与电化学性能的影响。结合X射线衍射仪(XRD),金相显微镜(OM),扫描电子显微镜(SEM)、能谱分析(EDS)及腐蚀电化学等材料表征手段对SLM TMZF试样的物相分布、微观组织结构、元素分布及耐腐蚀性能进行了对比分析。结果表明,单质混粉制备的SLM-β-1试样与中间合金混粉制备的SLM-β-2试样的组织中都含有大量的β-Ti组织,SLM-β-1试样在Bode图中显示出更高的阻抗,Nyquist图中SLM-β-1试样的容抗弧半径要大于SLM-β-2试样,动电位极化曲线中SLM-β-1试样的钝化膜击破电位要高于SLM-β-2试样。综合对比发现单质混合粉末SLM-β-1试样的耐腐蚀性能要优于中间合金混合粉末SLM-β-2试样的耐腐蚀性能。

In order to investigate the electrochemical corrosion behavior of selective laser melting(SLM)Ti-12 Mo-6 Zr-2 Fe(TMZF)βtitanium alloy,pure Mo powders and Mo-Fe master alloy powders were used to form mixed powders for laser additive manufacturing.The effect of master alloy powders on the microstructure and electrochemical properties of TMZF alloy sample was studied.The corrosion electrochemical properties of SLM TMZF samples fabricated via the two different mixed powders were systematically studied and compared.Phase composition,microstructural characteristics,elements distribution and corrosion resistance of the SLM TMZF samples were investigated using XRD,OM,SEM,EDS and electrochemical corrosion(EC).Results show that both SLM-β-1(prepared by mixing a variety of pure metal powders)and SLM-β-2(prepared by mixing intermetallic compounds powders)samples contain a large amount ofβ-Ti microstructure.SLM-β-1 sample show higher impedance in Bode plots.The capacitive arc radius of SLM-β-1 sample is larger than that of SLM-β-2 sample in Nyquist plots.The breakdown potential of passive film of SLM-β-1 sample in potentiodynamic polarization curve is higher than that of SLM-β-2 sample.Comprehensive comparison show that the corrosion resistance of SLM-β-1(prepared by mixing a variety of pure metal powders)sample is better than that of SLM-β-2(prepared by mixing intermetallic compounds powders)sample under different mixed powders.