| CHANG Zexin,BI Wenhao,GE Yaqiong,SONG Yue,WANG Wenxian.Effect of Nb on the Microstructure and Mechanical Properties of Zr-based Metallic Glass Prepared by Selective Laser Melting[J],54(7):139-150 |
| Effect of Nb on the Microstructure and Mechanical Properties of Zr-based Metallic Glass Prepared by Selective Laser Melting |
| Received:June 25, 2024 Revised:August 29, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.07.012 |
| KeyWord:selective laser melting bulk metallic glass composites microstructure mechanical behavior of nanoindentation |
| Author | Institution |
| CHANG Zexin |
Taiyuan University of Science and Technology, Taiyuan , China |
| BI Wenhao |
Taiyuan University of Science and Technology, Taiyuan , China |
| GE Yaqiong |
Taiyuan University of Science and Technology, Taiyuan , China |
| SONG Yue |
Taiyuan University of Science and Technology, Taiyuan , China |
| WANG Wenxian |
Taiyuan University of Technology, Taiyuan , China |
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| Abstract: |
| Bulk metallic glasses exhibit excellent physical, chemical and mechanical properties, which make them widely used in structural and functional material fields. However, bulk metallic glasses are constrained in their application due to intrinsic brittleness and size limitation of conventional preparation techniques. To address this issue, the work aims to introduce a reinforcement phase to improve the toughness of bulk metallic glass. The Zr-based bulk metallic glass composites with varying Nb particle contents (0%, 1%, 5%, and 10%, mass fractions) were successfully prepared by the selective laser melting technique. The phase composition analysis of the raw material and prepared samples was carried out by the X-ray diffraction, and the microstructure and morphology of different micro-zones (molten pool zone, remelting zone, and heat-affected zone) of the metallic glass composites and the distribution of internal Nb particles were observed by a scanning electron microscope. Moreover, transmission electron microscope and energy dispersive spectrometer were used to examine the interfacial morphology between Nb particles and the metallic glass matrix, and the nanoindentation test was conducted to analyze the mechanical properties of different micro-zones in the samples. The flow state of the molten pool was further analyzed by numerical simulation during selective laser melting process. Eventually, the effects of varying Nb particle contents on the forming quality, microstructure and morphology, and mechanical properties of the metallic glass composites were systematically investigated. The results showed that Nb particles were uniformly distributed in the metallic glass matrix with well-combined interfaces between the Nb particles and the metallic glass matrix. Moreover, some Zr, Ti, and Nb elements mainly dispersed in the interface, and no new crystalline phases were produced. However, some defects of porosity and microcracks were observed in the metallic glass composites. As the Nb particle content increased, the sample deformation and internal microcracks decreased, while porosity increased. This was attributed to the addition of Nb particles that reduced the mobility of the molten pool during selective laser melting process. The metallic glass composites exhibited different microstructure characteristics in various micro-zones due to the distinct temperature field characteristics experienced during the forming process. Specifically, the molten pool zone was a fully amorphous structure, while the remelting zone and the heat-affected zone consisted of nanocrystals and an amorphous phase due to the reheating effect. Additionally, nanoindentation tests demonstrated that the crystalline heat-affected zone exhibited the maximum hardness, followed by the remelted zone and the glassy molten pool zone. As the Nb particle content increased, the overall hardness, elastic modulus and fracture toughness of the metallic glass composites gradually increased. When the laser power was 90 W and the Nb content was 10%, the elastic recovery and fracture toughness of the metallic glass composites reached the maximum values of 0.066 and 4.852 MPa.m1/2, respectively. In conclusion, the addition of Nb particles promotes the initiation and propagation of multiple shear bands within the material, effectively inhibiting the propagation of the major shear band, thereby improving the toughness of the metallic glass composites. This work offers deep insights into formation and broad applications of metallic glass in additive manufacturing fields. |
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