Effect of Pre-Existing Nuclei on Crystallization during Laser Welding of Zr-Based Metallic Glass


In this study, experiments are carried out to demonstrate that in laser welding of a Zr-based (Zr52.5Ti5Al10Ni14Cu17.9) bulk metallic glass (BMG), pre-existing nuclei nucleus density has significant influence on its crystallization behavior. Based on the classical nucleation/growth theory, it is concluded that a small amount of pre-existing nuclei in a BMG can shift the time-temperature-transformation (TTT) curve from a well-known 'C-shape' to a 'ε-shape.' This result provides fundamental understanding on why the shape of the TTT curve for a heating process is different from that for a cooling process for the same BMG. Two quality factors were defined as a measure of the effect of pre-existing nucleus density. By integrating the classical nucleation/growth theory with the heat transfer model, the evolution of crystalline phase during laser welding for a BMG with pre-existing nuclei was studied, and the modeling predictions compared favorably with the experimental results.


Mechanical and Aerospace Engineering


The authors would like to acknowledge the financial support by the Department of Energy (grant number DE-FE0012272) and the University of Missouri System (award number Fast Track-16002R).

Keywords and Phrases

Amorphous alloys; Crystallization; Laser processing; Metallic glasses; Nucleation and growth

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Document Type

Article - Journal

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© 2019 Elsevier B.V., All rights reserved.

Publication Date

01 Jun 2019