Zr67.8Cu24.7Al3.43Ni4.07非晶合金激光焊接晶化控制及组织性能分析

Crystallization control and microstructural properties of laser welded Zr67.8Cu24.7Al3.43Ni4.07 bulk metallic glasses

对Zr67.8Cu24.7Al3.43Ni4.07非晶合金进行激光焊接,研究激光功率和焊接速度变化对接头不同区域微观组织的影响,阐述非晶合金激光焊接接头晶化控制的工艺调控规律,并分析接头不同区域的微观结构特征与其硬度之间的关系.结果表明,采用高焊速及高能量密度的激光焊接有利于使Zr67.8Cu24.7Al3.43Ni4.07非晶合金接头的熔化区保持非晶态结构,同时伴随少量纳米晶产生.热影响区的晶化现象明显,激光功率对接头完全焊透具有较大影响,通过降低激光功率或提高焊接速度以减小热输入,热影响区的晶化程度得到有效控制.焊后接头的熔化区硬度略高于母材,而热影响区的硬度相比于母材显著降低.

Laser welding was employed to weld Zr67.8Cu24.7Al3.43Ni4.07 bulk metallic glasses(BMGs).The effects of laser power and welding speed on the microstructures of different regions in the joints were studied.The crystallization control law of laser welded BMG joints is expounded,and the relationship between microstructure characteristics and hardness of as-welded joints is discussed.The results showed that the laser welding technology with high welding speed and high energy density is beneficial to maintain the amorphous structure of the molten zone in Zr67.8Cu24.7Al3.43Ni4.07 BMG joints,accompanied by some nano-grains forming.The crystallization happening in heat affected zones is severe.Laser power has a great influence on the complete penetration of as-welded joints.The degree of crystallization in heat affected zones can be effectively controlled through lowering laser power or increasing the welding speed to reduce heat input.Vickers hardness tests reveal that the hardness of the molten zones of the welded joint is slightly higher than that of base material,and the hardness of heat affected zones is significantly lower than that of the base material.