Enhancement of chip breakability of aluminium alloys by controlling the solidification during direct chill casting
| Autor: | Zhongyun Fan, Carla Barbatti, N.S. Barekar, Martin Jarrett, Ivan Skalicky |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Equiaxed crystals
machinability Materials science melt Conditioning Machinability Intermetallic chemistry.chemical_element 02 engineering and technology 010402 general chemistry 01 natural sciences Aluminium Materials Chemistry grain structures Composite material direct chill casting Mechanical Engineering Metals and Alloys 021001 nanoscience & nanotechnology Microstructure 0104 chemical sciences Forced convection extrusion chemistry Mechanics of Materials Casting (metalworking) Extrusion 0210 nano-technology |
| Popis: | Refinement and uniform dispersion of the free machining elements within the matrix is always desirable for aluminium billets produced by direct chill (DC) casting. The conventional grain refiner addition cannot ensure uniformity of microstructure and homogeneous distribution of insoluble or intermetallic phases. Melt conditioned direct-chill (MC-DC) casting is a key technology for producing uniform microstructure and refinement of secondary phases. This physical approach combines conventional vertical direct chill (DC) casting with a high shear device directly immersed in the sump for in situ microstructural control. Increased heat extraction rate due to forced convection, a larger temperature gradient at the solidification front and a shallower sump contribute to fine equiaxed dendritic grains with fine dendritic arm spacing that favor the fine and uniform distribution of second phase particles in the as-cast billet. This trend of the microstructural features was preserved even after thermomechanical downstream processing, giving rise to much improved machinability for the extruded solid bars. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|