Variable-Frequency Ultrasonic Treatment on Microstructure and Mechanical Properties of ZK60 Alloy during Large Diameter Semi-Continuous Casting
| Autor: | Chaoyang Chu, Qichi Le, Xibo Wang, Qiyu Liao, Xingrui Chen |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
lcsh:TN1-997
Materials science Scanning electron microscope Nucleation magnesium alloy semi-continuous casting grain refinement mechanical properties ultrasonic treatment 02 engineering and technology 01 natural sciences 0103 physical sciences Ultimate tensile strength General Materials Science Magnesium alloy lcsh:Mining engineering. Metallurgy 010302 applied physics Metallurgy Metals and Alloys 021001 nanoscience & nanotechnology Microstructure Casting Continuous casting Ultrasonic sensor 0210 nano-technology |
| Zdroj: | Metals, Vol 7, Iss 5, p 173 (2017) Metals; Volume 7; Issue 5; Pages: 173 |
| ISSN: | 2075-4701 |
| Popis: | Traditional fixed-frequency ultrasonic technology and a variable-frequency ultrasonic technology were applied to refine the as-cast microstructure and improve the mechanical properties of a ZK60 (Mg–Zn–Zr) alloy during large diameter semi-continuous casting. The acoustic field propagation was obtained by numerical simulation. The microstructure of the as-cast samples was characterized by optical and scanning electron microscopy. The variable-frequency ultrasonic technology shows its outstanding ability in grain refinement compared with traditional fixed-ultrasonic technology. The variable-frequency acoustic field promoted the formation of small α-Mg globular grains and changed the distribution and morphology of β-phases throughout the castings. Ultimate tensile strength and elongation are increased to 280 MPa and 8.9%, respectively, which are 19.1% and 45.9% higher than the values obtained from billets without ultrasonic treatment and are 11.6% and 18.7% higher than fixed-frequency ultrasound treated billets. Different refinement efficiencies appear in different districts of billets attributed to the sound attenuation in melt. The variable-frequency acoustic field improves the refinement effect by enhancing cavitation-enhanced heterogeneous nucleation and dendrite fragmentation effects. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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