强磁场处理固态铝基复合材料的组织和性能

发布时间：2018-03-19 20:34

本文选题：铝基复合材料　切入点：强磁场　出处：《稀有金属材料与工程》2017年05期 　论文类型：期刊论文

【摘要】：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。
[Abstract]:The solid Al_2O_3 reinforced 7055 aluminum matrix composites were treated with pulsed magnetic field under different magnetic induction intensities. After pulsed magnetic field treatment, the dislocation density of aluminum matrix composites increased with the increase of magnetic induction intensity. The reason lies in the increase of dislocation strain energy and the change of the state of dislocation pinning free radical. With the increase of magnetic induction intensity, the orientation of precipitates decreases and the quantity and size increase. The precipitated phase at grain boundary changed from continuous state to disconnected state, the number of precipitated phase decreased, the size of precipitated phase increased, and there were obvious precipitation bands without precipitation. These phenomena are mainly due to the effect of magnetic field to enhance the diffusion of solute atoms and vacancies in the crystal. With the increase of distortion energy, the release of internal stress provides a driving force for precipitation and growth. With the increase of magnetic induction intensity, the mechanical properties show a tendency of first increasing and then decreasing. The elongation and microhardness reached 548.04 MPA 17.235% and 1224 MPa respectively, which increased 10.3% and 20.7MPa, respectively. The improvement of mechanical properties was mainly due to the dislocation strengthening and the second phase strengthening caused by the increase of dislocation density.
【作者单位】：江苏大学;
【基金】：国家自然科学基金(51371091,51174099)
【分类号】：TB333

【相似文献】