【摘要】 采用脉冲激光技术对原位生成TiB2/ZL101铝基复合材料进行焊接,并分析了脉冲频率对焊缝成形及其微观组织、气孔和TiB2粒子在焊缝中分布的影响.结果表明:脉冲激光焊缝成形较好,焊缝内气孔数量较少,焊接后母材中团簇的TiB2粒子变得细小弥散且比母材分布更均匀;当脉冲频率增至200 Hz时,搅拌作用减弱且焊缝内气孔增多,TiB2粒子的弥散分布也相对减弱,激光穿透深度随着脉冲频率的增加而减小;激光焊接时,焊缝呈现出细小的等轴晶组织,在凝固过程中TiB2粒子被界面前沿推移至晶界处,使得其在焊缝内的硬度增加且分布较均匀,焊接后TiB2粒子未与铝基体发生界面反应而保持了对复合材料的增强效果.更多还原

【Abstract】 Pulsed laser welding of in situ TiB₂ particulate reinforced ZL101 aluminum matrix composites was carried out.The effects of pulse frequency on the formation of bead and microstructure were studied.The results show that the formation of bead is good,and the porosity is decreased due to the effect of stirring of pulsed laser on the molten pool.The clusters of TiB₂ get finer and distribute more homogeneously in the bead than that in the base metal.The stirring effect decreases when the pulse frequency is up to 200 Hz so that much porosity occurs and the clusters get larger.Moreover,the penetration depth is decreased with the pulse frequency increasing.The grain is very fine in the bead and TiB₂ particles are located at the grain boundary.The values of hardness are uniform in the bead,higher than that in the base metal.There is no interface reaction to produce brittle products between the TiB₂ and Al matrix so that it keeps the strengthening effects of reinforcement.更多还原