Chin-Chun Chang

Effect of Laser Welding on Properties of Dissimilar Joint of Al-Mg-Si and Al-Mn Aluminum Alloys

This study discusses the welding properties for the components of an aluminum-alloy ultra-high vacuum chamber and beam position monitor (BPM). The welding parameters include the modes of laser output (pulsed wave and continuous wave), welding speed, shield gas flow, welding bead structure, and focusing distance. The results showed that the welding defect rate of the pulsed wave type was larger than that of the continuous wave type. The crack in the welding bead reduced with decreasing welding speed. The fusion penetration of the welding bead was higher when the focusing distance was long enough to deepen into the welding material. Weld morphology during the experimental process revealed the proper flow of shield gas. The adaptability design of the welding bead structure in the preceding processes had more effect on overall welding structure and morphology.

Comparative study of Ar-implanted Ti-Zr-V non-evaporable getter films on the Al-alloy substrate

Original and Ar-implanted Ti-Zr-V non-evaporable getter (NEG) films were characterized using scanning electron microscope, X-ray diffractometer, electron spectroscopy for chemical analysis, and transmission electron microscopy. Similar properties and results were observed in the surface morphology, the composition, and the crystalline structure for original and implanted Ti-Zr-V films. However, the thermal activation temperature were increased for implanted films. The analysis of implanted Ti-Zr-V films revealed that defects formed in the upper layers of the films can trap diffused gaseous atoms from the surface into the Ti-Zr-V films. Therefore, the thermal activation reaction of Ti-Zr-V films would be affected due to implantation-induced defects in the films. We show directly that the thermal activation reaction of Ti-Zr-V films are changed by the existence of defects in the getter films.Original and Ar-implanted Ti-Zr-V non-evaporable getter (NEG) films were characterized using scanning electron microscope, X-ray diffractometer, electron spectroscopy for chemical analysis, and transmission electron microscopy. Similar properties and results were observed in the surface morphology, the composition, and the crystalline structure for original and implanted Ti-Zr-V films. However, the thermal activation temperature were increased for implanted films. The analysis of implanted Ti-Zr-V films revealed that defects formed in the upper layers of the films can trap diffused gaseous atoms from the surface into the Ti-Zr-V films. Therefore, the thermal activation reaction of Ti-Zr-V films would be affected due to implantation-induced defects in the films. We show directly that the thermal activation reaction of Ti-Zr-V films are changed by the existence of defects in the getter films.