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Investigation Of Laser Welding Of Zr43Cu50Al7 Bulk Amorphous Alloy

Posted on:2007-03-14Degree:MasterType:Thesis
Country:ChinaCandidate:B YeFull Text:PDF
GTID:2121360242961173Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
As engineering material of a new type bulk amorphous alloys(BMG)possess many outstanding properties such as high strength, high stiffness, excellent corrosion resistance, improved abrasion resistance and good soft-magnetic properties which crystalline alloys have not in virtue of the unique microstructure. So bulk amorphous alloys take on great potential application prospect in mechanical, electric, electron, avigation, et al. engineering region. However the lack of weldablity of bulk amorphous alloys limits their application as structural material all through. Be to make bulk amorphous alloys form components so that they acquire extensive application in engineering. Therefore, the investigation of the weld character of bulk amorphous alloys should be expedited.Laser welding technology has been adopted to weld Zr-base bulk amorphous alloy Zr43Cu50Al7 (at%) with a high glass-forming ability. The structure of joints under different technical parameters has been researched, and the crystallization behavior of the bead and heat-affected zone (HAZ) during the thermal cycle of welding has been briefly discussed. The results shows that excellent joints have been obtained and there is no visible defect, pore or crack in both the bead and HAZ when the output power of laser beam is 1200W, the diameter of laser beam is 0.3mm and the scanning velocity is 8m/min. No crystal is observed in both the bead and HAZ. But crystallization occurs in both the bead and HAZ to different extent under the same conditions while the scanning velocity is 2m/min and 4m/min. The temperature fields of bulk amorphous alloys during laser weld have been numerically simulated by the finite element method. The heat cycle curves of three special points in the bead and HAZ have been obtained, on the base of which the result of the weld experiment is detailedly analyzed.The structure relaxation phenomenon and crystallization behavior of Zr43Cu50Al7 bulk amorphous alloy have been studied by differential scanning calorimetry in the mode of continuous heating in order to clearly understand the crystallization behavior of bulk amorphous alloys in the bead and HAZ after welding.
Keywords/Search Tags:Laser welding, Zr-base bulk amorphous alloy, Crystallization behavior, Structure relaxation, DSC
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