Jt. Wang et al., The influence of temperature and surface conditions on surface absorptivity in laser surface treatment, J APPL PHYS, 87(7), 2000, pp. 3245-3253
A one-dimensional, transient, inverse heat conduction problem is implemente
d to investigate the influence of temperature and surface conditions on sur
face absorptivity in the laser surface heating process. Analysis includes t
he utilization of the conjugate gradient method (CGM), with temperatures me
asured near the heated surface. To increase efficiency and accuracy of the
calculation, the result retrieved from the least-square method is used as a
n initial guess for the CGM. Results show that absorptivity decreases when
the temperature exceeds a certain value. This decrease is related to struct
ural transformation during the temperature rise. As the surface temperature
nears the melting point, the decreasing trend inverts and absorptivity inc
reases. This final abrupt rise is caused by the phase transformation from o
rder to disorder. Additionally, absorptivity is related to surface conditio
ns such as absorption-enhancing coatings and surface roughness. (C) 2000 Am
erican Institute of Physics. [S0021-8979(00)02307-0].