研究了脉冲磁场对TC4钛合金微观结构的影响规律，发现经磁感应强度为2 T、脉冲频率为5 Hz、脉冲次数为 100次的脉冲磁场处理后，TC4钛合金的位错密度及晶界角度会发生显著变化。XRD测试结果显示，经脉冲磁场处理后TC4钛合金的位错密度提高约10.9%。采用EBSD测试得到TC4钛合金微区的KAM分布，发现经脉冲磁场作用后，TC4钛合金的位错密度发生显著变化，具体表现为：晶内位错分布更加均匀，局部高位错密度区消失；晶界附近的位错分布发生变化，同时晶界角度发生改变，小角度晶界减少而重位点阵(CSL)晶界(Σ11)增多。讨论了脉冲磁场对TC4钛合金微观组织影响的可能原因：脉冲磁场引起位错钉扎处的电子能态发生转变，使钉扎处空位或杂质原子易于移动。位错在材料内应力场提供的弹性能作用下更易脱钉扎，从而使得位错分布发生变化，材料微观组织发生改变。

In this work, the effect of pulsed magnetic treatment (PMT) on the microstructure of TC4 titanium alloy was investigated. TC4 titanium alloy is widely used in the manufacture of the blade of aviation engine. The microstructure of TC4 titanium alloy determines its property. PMT is a novel method used to modify the microstructures of alloys and has been explored in several papers recently. PMT has many advantages in the aspect of efficiency, energy-saving, non-deformation, etc. Therefore, the effect of PMT on the microstructures of TC4 titanium alloy was explored in this work. The variation of the dislocation density and the grain boundary angle of TC4 titanium alloy was observed after PMT. In the experiment, the magnetic induction density is 2 T, the pulse frequency is 5 Hz and the pulse number is 100. According to XRD tests, the dislocation density in TC4 alloy after PMT increased about 10.9%. KAM maps in EBSD test were used for evaluating the same area's dislocation density of the TC4 alloy before and after PMT. The dislocation distribution of TC4 titanium alloy changes notably: the in-grain dislocation density became more homogeneous and some local high-density areas disappeared, the distribution of dislocation near grain boundaries caused the angles of the grain boundaries altered and the fraction of low-angle grain boundaries decreased while the fraction of Σ11 grain boundaries (CSL grain boundary) increased. The motivation mechanism of the dislocation in TC4 titanium alloy under PMT was speculated based on the experimental results and some previous researches. The PMT may change the energy state of the electrons in pinning area of dislocations, which accelerates the electrons transformation from singlet state to triplet state and then increases the mobility of the vacancy or impurity atoms so that the dislocation de-pinning could occur under the original stress field and thus leads to dislocation movement and transformation of microstructure.