The Crystallization Mechanism of Zr-Based Bulk Metallic Glass during Electron Beam Remelting

Xiaopeng Li; Zeyu Zhang; Yi Yang; Jikang Fan; Jian Kong; Kehong Wang

doi:10.3390/ma13163488

The Crystallization Mechanism of Zr-Based Bulk Metallic Glass during Electron Beam Remelting

Materials (Basel). 2020 Aug 7;13(16):3488. doi: 10.3390/ma13163488.

Authors

Xiaopeng Li¹, Zeyu Zhang¹, Yi Yang¹, Jikang Fan¹, Jian Kong¹, Kehong Wang¹

Affiliation

¹ College of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.

Abstract

Bulk metallic glasses (BMGs) are promising for multifunctional and structural application in different industries. However, the limited size of BMGs hinders their further application. The welding of BMGs has shown the possibility of getting rid of the casting size limitation. The heat-affected zone (HAZ) and fusion zone (FZ) often undergo severe crystallization during the welding process. It is still unclear whether the crystallization occurs during the heating process or the cooling process. To figure out the crystallization mechanisms of Zr-based BMGs during the electron beam welding process, the Zr-based BMGs with the composition of Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 were remelted by electron beam. The microstructures of the HAZ and the remelting zone (RZ) were analyzed. The thermal field of the electron beam welding was obtained by the finite element method (FEM). The critical conditions for crystallization during the heating and cooling processes were obtained by differential scanning calorimetry (DSC) and the Kissinger equation. The results show that the Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 in the HAZ undergoes severe crystallization, while the Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 in RZ keeps amorphous state after the remelting process. The low cooling rate in the HAZ is responsible for its crystallization.

Keywords: BMGs; FEM; critical cooling or heating rate; electron beam remelting; microstructures.

Abstract

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