摘要
This paper reports on laser surface remelting experiments performed on a Zn-2wt.Cu hypoperitectic alloy by employing a 5kW CW CO2 laser at scanning velocities between 6 and 1207mm/s. The growth velocities of the microstructures in the laser molten pool were accurately measured. The planar interface structure caused by the high velocity absolute stability was achieved at a growth velocity of 210 mm/s. An implicit expression of the critical solidification velocity for the cellular-planar transition was carried out by nonlinear stability analyses of the planar interface. The results showed a better agreement with the measured critical velocity than that predicted by M-S theory. Cell-free structures were observed throughout the whole molten pool at a scanning velocity of 652 mm/s and the calculated minimum temperature gradient in this molten pool was very close to the critical temperature gradient for high gradient absolute stability (HGAS) of the η phase. This indicates that HGAS was successfully achieved in the present experiments.
源语言 | 英语 |
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文章编号 | 042 |
页(从-至) | 1631-1637 |
页数 | 7 |
期刊 | Chinese Physics |
卷 | 15 |
期 | 7 |
DOI | |
出版状态 | 已出版 - 1 7月 2006 |