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- Dugic, Izudin, 1962-, et al.
(author)
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The effect of chemical composition on the metal expansion penetration in grey cast iron
- 1999
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Reports (other academic/artistic)abstract
- In some grey cast iron components which are cast in sand moulds, the metal sometimes penetrates into the mould producing defects and causing difficulties when cleaning the components. To improve knowledge of the metal penetration mechanism a series of test castings was performed at ITT Flygt’s foundry where the influence of chemical composition was studied. The chemical composition of the melt was changed in the ladle before pouring. The result showed that the carbon and phosphorus content had an influence on metal penetration. The metal penetration tendency decreased when decreasing the carbon content as well as when increasing the phosphorus content. The penetration areas were analysed in a Scanning Electron Microscope (SEM) with Energy Dispersive Analysis (EDS). The analysis showed that the average chemical composition in the penetration zones was close to the initial composition of the alloy. Consequently, no significant macro segregation of carbon or phosphorous could be observed. The whole casting process was simulated with the software MAGMAsoftTM, in order to investigate the solidification characteristics as well as the porosity formation in the casting studied. For this, a special module for cast iron was used, MAGMAironTM, where nucleation and growth of all relevant phases are considered. During simulation it is possible to detect the areas where porosities are likely to be formed. The results show that expansion penetration generally occurs in the same areas depending on the mode of solidification. The inoculation and solidification behaviour will result in excess or deficiency of the metal at the end of solidification, which will lead to either metal penetration or formation of porosities.
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- Ullakko, Kari, et al.
(author)
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Isothermal Martensite Transformation of Fe-Ni-C Alloys as a Function of Hydrostatic Pressure
- 1990
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In: Materials Science Forum volumes 56-58. - Zürich : Trans Tech Publiations. ; , s. 197-200
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Conference paper (peer-reviewed)abstract
- Isothermal martensite transformation as a function of hydrostatic pressure was studied in Fe-Ni-C alloys. It was observed that the transformation was much the same as it happens as a function of time. Any noticeable differences in the morphology between isothermal and athermal martensite were not seen.
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- Recina, Viktor, 1968, et al.
(author)
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Sample preparation and microstructural characterization of the gamma titanium aluminide Ti-48Al-2W-0.5Si
- 1997
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In: Materials Characterization. - 1044-5803. ; 38:4-5, s. 287-300
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Journal article (peer-reviewed)abstract
- Preparing samples that faithfully reveal all microstructural features in γ-TiAl-base alloys for both optical and scanning electron microscope studies is fraught with difficulties. This study demonstrates that satisfactory results can be obtained through mechanical grinding, polishing, and proper etching. A preparation recipe is presented. Nine lots of investmentcast γ-TiAl material with the nominal composition of Ti-48Al-2W-0.5Si have been characterized through optical and scanning electron microscope examinations. The study shows that a small depletion in Al content has a large effect on the microstructure. The duplex microstructure with a lamellar Full-size image (
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- Rao, K. Hanumantha, et al.
(author)
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Size effect of the mode II fracture toughness of rock
- 1999
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In: Rock mechanics for industry. - Rotterdam : Balkema Publishers, A.A. / Taylor & Francis The Netherlands. - 9058091007 ; , s. 1117-1123
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Conference paper (peer-reviewed)abstract
- A new method, compression-shear test, has been developed for determining the mode II fracture toughness K (sub IIC) of rock. The effect of the specimen thickness B, the dimensionless notch length a/W as well as the notch inclination angle alpha on the determination of K (sub IIC) has been experimentally studied. The results show that the apparent mode II fracture toughness K (sub c) decreases as B and a/W increase and becomes constant when B> or =70 mm (i.e. cubic specimen) and a/W>0.5. The K (sub c) is almost independent of alpha in the range of 65 degrees -75 degrees . The constant K (sub c) is about 2-3 times that of mode I fracture toughness K (sub IC) and can be considered as the true mode II fracture toughness K (sub IIC) of rock.
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