Yuan Ding, Shao Shuaiqi, Guo Chunhuan, Jiang Fengchun, Wang Jiandong
Key Laboratory of Superlight Materials & Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China.
Key Laboratory of Superlight Materials & Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China.
Ultrason Sonochem. 2021 May;73:105472. doi: 10.1016/j.ultsonch.2021.105472. Epub 2021 Jan 21.
The formation of the coarse columnar crystal structure of Ti-6Al-4V alloy in the process of additive manufacturing greatly reduces the mechanical performance of the additive manufactured parts, which hinders the applications of additive manufacturing techniques in the engineering fields. In order to refine the microstructure of the materials using the high intensity ultrasonic via the acoustic cavitation and acoustic flow effect in the process of metal solidification, an ultrasonic vibration technique was developed to a synchronous couple in the process of Laser and Wire Additive Manufacturing (LWAM) in this work. It is found that the introduction of high-intensity ultrasound effectively interrupts the epitaxial growth tendency of prior-β crystal and weakens the texture strength of prior-β crystal. The microstructure of Ti-6Al-4V alloy converts to fine columnar crystals from typical coarse columnar crystals. The simulation results confirm that the acoustic cavitation effect applied to the molten pool created by the high-intensity ultrasound is the key factor that affects the crystal characteristics.
在增材制造过程中，Ti-6Al-4V合金粗柱状晶结构的形成极大地降低了增材制造零件的力学性能，这阻碍了增材制造技术在工程领域的应用。为了利用金属凝固过程中的声空化和声流效应，通过高强度超声细化材料的微观结构，本研究开发了一种超声振动技术，使其在激光送丝增材制造（LWAM）过程中实现同步耦合。研究发现，引入高强度超声有效地中断了初生β相晶体的外延生长趋势，并削弱了初生β相晶体的织构强度。Ti-6Al-4V合金的微观结构由典型的粗柱状晶转变为细柱状晶。模拟结果证实，施加于由高强度超声产生的熔池的声空化效应是影响晶体特性的关键因素。
