Description

This sample shows the typical structure of silal, irons with high Si content (5.5-7.9 wt%). It is a grey cast iron alloyed with 4-6wt% Si to provide good oxidation resistance. The high Si content forms a dense, adherent iron silicate surface film, which is resistant to oxygen penetration. The flake graphite iron Silal was one of the first heat resisting cast irons developed. Spheroidal graphite Si irons have higher strength and improved ductility. The structure shows cored dendrites of ferrite with interdendritic flake graphite. A few white areas of Si carbide are also present.

Subjects

alloy | carbon | grey cast iron | iron | metal | silal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

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Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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This sample shows the typical structure of silal, irons with high Si content (5.5-7.9 wt%). It is a grey cast iron alloyed with 4-6wt% Si to provide good oxidation resistance. The high Si content forms a dense, adherent iron silicate surface film, which is resistant to oxygen penetration. The flake graphite iron Silal was one of the first heat resisting cast irons developed. Spheroidal graphite Si irons have higher strength and improved ductility. The structure shows cored dendrites of ferrite with interdendritic flake graphite. A few white areas of Si carbide are also present.

Subjects

alloy | carbon | grey cast iron | iron | metal | silal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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This sample shows the typical structure of silal, irons with high Si content (5.5-7.9 wt%). It is a grey cast iron alloyed with 4-6wt% Si to provide good oxidation resistance. The high Si content forms a dense, adherent iron silicate surface film, which is resistant to oxygen penetration. The flake graphite iron Silal was one of the first heat resisting cast irons developed. Spheroidal graphite Si irons have higher strength and improved ductility. The structure shows cored dendrites of ferrite with interdendritic flake graphite. A few white areas of Si carbide are also present.

Subjects

alloy | carbon | grey cast iron | iron | metal | silal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | manganese | metal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | metal | spheroidal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | metal | spheroidal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | metal | spheroidal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | metal | spheroidal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Cast iron is a brittle material and it is advantageous to process it in such a way to improve its ductility. The brittleness is partially due to the graphite flakes which act as nucleation sites for cracks. Therefore it is an advantage to have the graphite present as spheres. This can be achieved by a heat treatment regime or by the addition of a small amount of Mg which poisons the graphite growth directions.

Subjects

alloy | carbon | cast iron | iron | metal | spheroidal | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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Description

Chemical vapour deposition (CVD) allows the synthesis of high purity nanotubes of controlled length and diameter. The nanotubes in this specimen were formed in the heated zone of the apparatus whilst using ferrocene dissolved in toluene. The fibres are of high purity and their diameters range from 400 to 500 nm.

Subjects

carbon | carbon nanotube | chemical vapour deposition (cvd) | ferrocene | nanotube | polymer | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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The base of the cup is the least strained part of the sheet. Nevertheless, residual strain, increasing with radius, is evident when the specimen is viewed between crossed polars. The polymer chains are more highly aligned where the strain is greatest and this leads to greater birefringence (rotation of polarised light). Hence a circumferential pattern of colours is observed. If heated above the glass-transition temperature of PET (70-80 °C), the cup will tend to retract towards its unstrained form of a sheet. The dark 'Maltese cross', spreading out horizontally and vertically from the centre, indicates the extinction directions or the orientations of the two polarising films, where the intensity of transmitted light is lowest. Note: most clear plastic cups are made from polystyrene (PS)

Subjects

alignment | birefringence | cup | drawing | polyester | polyethylene terephthalate (pet) | polymer | strain | thermoforming | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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The colours in the image are the result of birefringence and relate to the residual strain in the polystyrene. The pattern of strain is indicative of the flow of material during the injection process and it highlights the injection point (known as a 'gate') at the end of the ruler; the molecular alignment is greatest near this point. Towards the edges of the ruler and along its length, the material becomes more relaxed and as the molecular alignment falls, the retardation of light is less. If heated above the glass transition temperature of polystyrene (about 100 °C), the material will tend to relax, particularly along the centreline, near the gate. This will result in a wrinkled form.

Subjects

alignment | birefringence | injection moulding | polymer | polystyrene (ps) | ruler | sprue | strain | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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The colours in the image are the result of birefringence and relate to the residual strain in the polystyrene. The pattern of strain is indicative of the flow of material during the injection process and it highlights the injection point (known as a 'sprue') which can also be identified by a small lump on the surface; the molecular alignment is greatest near this point. Towards the edges of the ruler and along its length, the material becomes more relaxed and as the molecular alignment falls, the retardation of light is less. If heated above the glass transition temperature of polystyrene (about 100 °C), the material will tend to relax, particularly near the sprue. This will result in a wrinkling of the component.

Subjects

alignment | birefringence | injection moulding | polymer | polystyrene (ps) | sprue | doitpoms | university of cambridge | micrograph | corematerials | ukoer | Engineering | H000

License

Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales http://creativecommons.org/licenses/by-nc-sa/2.0/uk/ http://creativecommons.org/licenses/by-nc-sa/2.0/uk/

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