The Study of Second Dendrite Arm Spacings of Argon-atomised Rene' 95 Alloy Powder

The second dendrite arm spacings were measured by the method of stereolog-ical metallography method. The cooling rate is determined by the Newton's Cooling Law, and the time required for entirely solidification of powder particles is calculated as well. The second dendrite arm space of Rene'95 alloy powder is related with the particle size, cooling rate、solidifying rate and the time needed for solidification. The relationships are represented as d=0.242D0.489, d=102.9v^-0.488, d=2.47 (dε/dt)^-0.492, and d=39.28tk^0.245.
The results of the study made it clear that the commom equations of casting, i, e, d=av^-n, d=btⁿ, where n is between l/3-l/2, can be applied to the olidification process of argon-atomised Rene'95 alloy powder particles.