2005 Fiscal Year Final Research Report Summary
In-situ observation of effect of tramp element on peritectic reaction and transformation of iron based alloy
| Project/Area Number |
16560646
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Metal making engineering
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| Research Institution | TOHOKU University |
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Principal Investigator |
SHIBATA Hiroyuki Tohoku university, Institute of Multidisciplinary Research for Advanced Materials, Lecturer, 多元物質科学研究所, 講師 (50250824)
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| Project Period (FY) |
2004 – 2005
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| Keywords | peritectic reaction / peritectic transformation / confocal scanning laser microscope / iron-copper alloy / iron-nickel alloy |
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| Research Abstract |
The mixture of pure iron and copper was melted to produce an ingot of the alloys with an arc melting furnace. The rectangular shape sample was machined from the cast ingot. The rectangular shape sample was contained in alumina crucible and heated under high purity argon atmosphere by using an infrared image furnace. The changes of the sample were observed with a confocal scanning microscope at elevated temperatures. The rectangular crucible plays an important role in order to have the sample unidirectionally solidify. The characteristics of liquid-> delta ferrite and delta ferrite -->gamma austenite transformation in Fe-Cu and Fe-Ni alloys and of the peritectic solidification of those alloys, have been dynamically observed in situ with a confocal scanning laser microscope combined with an infrared image furnace. The unique sequence, morphologies, and rates of these transformations have been determined under a temperature gradient, in unidirectional solidification experiments. The δ phase undergoes a peritectic reaction, with the lateral growth of γ along the L/δ boundary, and transforms into cellular γ very rapidly, far in excess of diffusion-controlled rate, indicating that the transformation is a massive one. The growth rate of the γ phase is faster toward metastable δ than toward liquid. The temperatures of the phase transformations of the alloys were also measured by using a differential scanning calorimeter. The measured temperatures were compared with the observed phenomena of the alloys. Then, the observed temperatures were also tested, and the discussion would be possible under accurate temperature conditions. These observations have been discussed in terms of the constitutional undercooling description of solidification theory.
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Research Products
(2 results)
