The Zr55Al10Ni5Cu30 bulk metallic glass plate were successfully welded to crystalline aluminum plates by using a friction stir welding (FSW) method. The welded zone was examined. No defects, cracks or pores were observed and no other crystalline phases except for aluminum were found in the welded joint. The strength of the joint is higher than that of aluminum. The glassy phase in the stir zone keeps the amorphous state, showing a successful welding. The storage modulus softens over the glass transition. And the weldability was discussed according to this phenomena.
Zuoxiang QinCuihong LiHaifeng ZhangZhongguang WangZhuangqi HuZhiqiang Liu
The influence of Zr content on corrosion behaviors of the Ni61.5Nb 38.5xZrx(x=1,3,5,7,9 at.%) bulk metallic glasses(BMGs) in 1 M HCl aqueous solution was investigated by potentiodynamic polarization measurements and X-ray photo-electron spectroscopy(XPS).It was found that these BMG alloys possess superior corrosion resistance,that is,with large passive region of about 1.5 V and low passive current density(as low as 0.05 Am-2 for Ni61.5Nb31.5Zr7).XPS analysis indicates that the high corrosion resistance is attributed to the formation of Nb-and Zr-enriched surface films formed in the aggressive acid solution.The Zr substitution for Nb effectively reduces the Ni content,particularly the metallic state Ni content in the surface films,which depresses the electrical conduction of the surface films and reduces the passive current density,thus leading to the enhancement of the corrosion resistance of these Ni-Nb-Zr BMGs.These alloys may potentially be useful for engineering applications.
LI DengKeZHU ZhengWangZHANG HaiFengWANG AiMinHU ZhuangQi
