电子束增材制造TC4合金制备熔道特征的研究

Study on Characteristics of TC4 Alloy Single Track Prepared by Electron Beam Melting

利用电子束增材技术制备了TC4合金熔道,并改变扫描速度、束流和离焦电流等工艺参数,研究工艺参数对熔道表面形貌以及特征尺寸(熔深,熔宽,熔高和润湿角)的影响。研究表明,随着扫描速度的降低和电子束电流的增加,电子束线性能量输出增加,熔道宽度和连续性均有所提高。当其它参数不变,随着扫描速度的增加,熔道变得不连续甚至发生球化反应。扫描速度、束流和离焦电流均对熔池有较大的影响,随着扫描速度的降低以及束流的增加,熔深、熔宽和熔高都在增加;当离焦电流为3 mA时而熔深和熔宽最大,润湿角最小;电子束电流不变,随着扫描速度的增加,润湿角先增大后减小,宽高比下降。

A series of TC4 alloy single tracks were prepared by electron beam melting,and the effects of the process parameters such as scanning speed,beam current on the surface morphology and geometrical characteristics(re-melt depth,track width,track height,contact angle and aspect ratio)of a single track were investigated.The results show that with the decrease of scanning speed and the increase of beam current,the linear energy input increases and the width and continuity of single tracks are improved.When other parameters are fixed,with the increase of scanning speed,the single track becomes discontinuous and even the balling effect can be observed.The scanning speed,beam current and focus offset all have great influence on the melt pool.With the decrease of the scanning speed and the increase of beam current,the re-melt depth,track width,and track height increase.When the focus offset is 3 mA,the re-melt depth and track width are the maximum while the contact angle is the minimum.For the constant of beam current,with the increase of the scanning speed,the contact angle increases first and then decreases while the aspect ratio decreases.