Effect of extrusion temperature on microstructure and mechanical properties of a low-alloying and ultra-high strength Mg–Zn–Ca–Mn matrix composite containing trace TiC nanoparticles
| Autor: | Zhihao Zhu, Jungang Han, Kai-bo Nie, K.K. Deng |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
lcsh:TN1-997
010302 applied physics Toughness Nanocomposite Materials science Extrusion Metals and Alloys Mechanical properties 02 engineering and technology 021001 nanoscience & nanotechnology Microstructure 01 natural sciences Mechanics of Materials 0103 physical sciences Ultimate tensile strength Dynamic recrystallization Magnesium matrix nanocomposite Lamellar structure Strengthening mechanism Composite material 0210 nano-technology lcsh:Mining engineering. Metallurgy Eutectic system |
| Zdroj: | Journal of Magnesium and Alloys, Vol 8, Iss 3, Pp 676-691 (2020) |
| ISSN: | 2213-9567 |
| DOI: | 10.1016/j.jma.2020.04.006 |
| Popis: | Mechanical properties of microalloying Mg–2.2Zn–1.8Ca–0.5Mn (wt%) matrix composites reinforced by 0.5 wt% TiC nanoparticles before and after extrusion were investigated based on the detailed microstructural analysis. A uniform distribution of TiC nanoparticles was realized in the nanocomposite by the method of ultrasonic-assisted semisolid stirring. The morphology of eutectic Ca2Mg6Zn3 phases changed from plate-like in the free TiC nanoparticles region to lamellar in the dense TiC nanoparticles region for the as-cast nanocomposite. Both the grain structure and precipitates were obviously refined as the extrusion temperature decreased from 350 to 270 °C. The nanocomposite exhibited excellent tensile yield strength (352–428 MPa) which was governed by the extrusion temperature. The grain refinement strengthening with the contribution ratio of ∼80% to this strength increment was much higher relative to thermal expansion effect, Orowan strengthening and dislocation strengthening. Ultrafine recrystallized grain structure with a substantial of fine precipitates appeared in the nanocomposite extruded at 270 °C. The refined grain structure was not only due to dynamic recrystallization, but also the synergistic pinning effect of nano-TiCp, precipitated MgZn2 and α-Mn particles. The tensile toughness value of nanocomposite after extrusion improved with increasing the extrusion temperature. Massive micro-cracks formed along the remnant coarse Ca2Mg6Zn3 led to the structural failure during tension. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|