激光沉积成形用超声振动系统的研制

Development of ultrasonic vibration system in laser metal deposition

为了细化晶粒、均匀组织成分,将超声振动引入激光沉积成形系统中。针对沉积系统的结构特点,设计了超声振动系统,对其中的超声电源和换能器进行了选择,并对超声变幅杆进行了设计和计算;然后测试了系统性能,并采用工艺试验验证其效果;从试验试件的宏观形貌、内部组织两方面,分析了超声振动对沉积层组织的影响。结果表明施加超声作用后沉积层单道沉积高度变小,原本较长的枝晶被振动的各种效应打碎,晶粒得到细化。

Ultrasonic vibration is introduced to the LMD processes to refine the grain size and improve microstructural homogeneity. So ultrasonic vibration system is designed including its ultrasonic power supply, transducer and amplitude transformer. Then the performance tests is conducted. At last the paper applies ultrasonic vibration system to fabricate the sample and analyses its effect on its macroscopical appearances and microstructure by experiments. The results showed that the deposit layers thickness and the grain size changes smaller, which showed that the ultrasonic vibration make convection stronger and laser beam energy more homogeneous. In addition,it can break the longer dendrite to refine the grain.