2004 / DB reference year
PREV and NEXT link to numerically adjacent references for this YEAR.
CONTENTS links to the title list for this YEAR's references.
Author Fischer, P.; Karapatis, N.; Romano, V.; Glardon, R.; Weber, H.P. ; Institute of Applied Physics, Laser Materials Processing, University of Bern, 3012 Bern, Switzerland
Source Appl Phys A v 74 Issue:n 4 April 2002 p 467-474
Abstract A thermal model of the interaction of pulsed near-infrared laser radiation from a Nd:YAG laser was made, taking the measured powder properties such as reflectance, optical penetration depth and thermal conductivity into account. It allows an estimation of the evolution of two different temperatures: the average temperature of the powder (taken over the grains in a volume given by the laser beam diameter and the optical penetration depth) and the temperature distinction within a single grain. It showed that in pulsed mode consolidation can be achieved at much lower average power as the surface of the powder particles are molten but their cores remain at nearly room temperature. This leads to a much lower average temperature and therefore a dramatic decrease in residual thermal stresses in the finished piece. The results of the model were experimentally tested and confirmed. (Auth abstract) XX