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在不同磁感应强度下对固态Al_2O_3增强7055铝基复合材料进行了脉冲磁场处理。经脉冲磁场处理后,铝基复合材料的位错密度随磁感应强度的增加呈上升趋势,分析原因在于位错应变能增加和位错钉扎中心自由基对状态的改变。随着磁感应强度的提高,晶内析出相的取向性减小,数量和尺寸增加;晶界析出相由连续状态转变为断开状态,析出相数量减少、尺寸增大,并出现了明显的无沉淀析出带。这些现象主要源于磁场作用增强了晶体内部溶质原子和空位的扩散;畸变能增加、内应力的释放为析出相析出、长大提供了驱动力。力学性能随磁感应强度的增加,呈现出先升高、后降低的趋势。在B=3 T时,抗拉强度、延伸率和显微硬度达到了548.04 MPa、17.235%和1224 MPa,较处理前试样分别提高了10.3%、16.2%和20.7%。力学性能的改善主要源于位错密度增加造成的位错强化和第二相强化。
Solid state Al 2 O 3 reinforced 7055 aluminum matrix composites were treated by pulsed magnetic field under different magnetic induction. After pulsed magnetic field treatment, the dislocation density of the Al-based composites increases with the increase of the magnetic flux density. The reason for the analysis is the increase of the dislocation strain energy and the change of the free radical on the center of dislocation pinning. With the increase of the magnetic induction intensity, the orientation of precipitated phase decreases, the number and size increase; the precipitated phase in the grain boundary changes from a continuous state to an off state, the number of precipitated phases decreases, the size increases, and the obvious no Precipitation precipitation belt. These phenomena are mainly due to the effect of the magnetic field to enhance the diffusion of solute atoms and vacancies inside the crystal; the distortion can increase, and the release of internal stress provides the driving force for precipitation and growth. Mechanical properties with the increase of magnetic induction, showing the first increase, then reduce the trend. At B = 3 T, the tensile strength, elongation and microhardness reached 548.04 MPa, 17.235% and 1224 MPa, respectively, which were increased by 10.3%, 16.2% and 20.7% respectively compared with those before treatment. The improvement of mechanical properties is mainly attributed to the dislocation strengthening and the second phase strengthening caused by the increase of dislocation density.