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采用低能强电流(LEHC)脉冲改性技术处理TC4钛合金表面,利用扫描电子显微(SEM)、场发射扫描电镜(FESEM)、透射电子显微(TEM)和纳米压痕分析(NI)等方法对表面改性层组织进行表征,按照不同低能强电流脉冲改性工艺下改性层的组织特征,结合纳米压痕硬度试验,分析了脉冲电子束改性晶粒的细化机制。结果表明,脉冲电子束改性试样可分为熔化相变层、热影响层和基体三个区域;熔化相变层中的晶粒细化机制是脉冲电子束改性时随着温度的快速升高,表面层发生熔化后的重新结晶以及α相在β相中的析出;晶粒细化是表层纳米压痕硬度提高的主要原因。
The surface of TC4 titanium alloy was treated by low energy and high current (LEHC) pulse modification technique. The surface morphology of the TC4 titanium alloy was characterized by scanning electron microscopy (SEM), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and nanoindentation analysis Methods The microstructure of the surface modification layer was characterized. According to the microstructure of the modified layer under different low-energy high-current pulse modification techniques, the refinement mechanism of the impulse electron beam-modified grains was analyzed with the nanoindentation hardness test. The results show that the pulsed electron beam modified specimen can be divided into three regions: the molten phase change layer, the heat affected layer and the matrix. The grain refinement mechanism in the molten phase change layer is that with the rapid modification of the pulse electron beam, Increased, the recrystallization after the melting of the surface layer and the precipitation of α phase in the β phase; the grain refinement is the main reason for the increase of surface nanoindentation hardness.