The effect of managanese addition on the microstructure of W-Ni-Fe heavy alloy
The influence of Mn addition on the growth kinetics and morphology of W grains in W-Ni-Fe heavy alloy has been studied. The addition of Mn was performed by placing a compact of Mn powder on the sintered specimens containing constant Ni/Fe ratio of 8/2 but different W contents of 93 and 97 wt pct fol...
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Veröffentlicht in: | Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 1999-03, Vol.30 (3), p.627-632 |
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Sprache: | eng |
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Zusammenfassung: | The influence of Mn addition on the growth kinetics and morphology of W grains in W-Ni-Fe heavy alloy has been studied. The addition of Mn was performed by placing a compact of Mn powder on the sintered specimens containing constant Ni/Fe ratio of 8/2 but different W contents of 93 and 97 wt pct followed by resintering. The sintering and resintering treatments were carried out at a temperature of 1485 °C under a dry hydrogen atmosphere. The addition of Mn leads to the deviation of growth rate of W grains from the diffusion-controlled Ostwald ripening: the growth rate is initially enhanced and then decayed. The difference in the average grain radius between the alloys containing high and low W contents is decreased by the addition of Mn. The cause of the change in the growth rate of W particles with the addition of Mn is discussed in terms of the competitive soluble reactions of Mn and W atoms. The addition of Mn also results in the morphological change of W grains from roudish to angular shape. The addition of Mn into the matrix phase, which is artificially made, forms the dendritic W grains. From these results, it is found that the morphological change of W grains is closely related to the precipitation reaction of W atoms on the preferred orientation. |
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ISSN: | 1073-5623 1543-1940 |
DOI: | 10.1007/s11661-999-0054-4 |