کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5368123 | 1388385 | 2007 | 5 صفحه PDF | دانلود رایگان |

In this paper we determine the features of the thermophysical processes involved in the interaction of laser radiation with metals that have cryogenic temperature. To do so, we use a one-dimensional model that involves heating a semi-infinite solid by a point thermal source with a constant flux density. Temperature fields, heating and cooling rates in the laser-irradiated zone for iron and titanium at the ambient temperatures of 77 (liquid nitrogen), 293 and 573Â K were calculated. The intensity of the laser irradiation enabled the melting temperatures of 1933Â K and 1812Â K on the Ti and Fe surface, respectively, to be reached. The duration of the laser pulse was 4.5Â ms. We show that a drop in ambient temperature from 573 to 77Â K leads to a rise in cooling rate from 3.25Â ÃÂ 103 and 6.4Â ÃÂ 106Â K/s to 4.25Â ÃÂ 103 and 1.3Â ÃÂ 107Â K/s in the Ti and Fe targets, respectively. Agreement was good between the calculated depths of melting and phase transformation isotherms and the experimental depths of the interfaces of melting and heat-affected zones.
Journal: Applied Surface Science - Volume 254, Issue 4, 15 December 2007, Pages 821-825