采用分支理论对急冷过程中多定态现象的研究

通过一个简单模型模拟了合金Pd82Si18的急冷过程,分析实验上难以测定的热传输指数对凝固过程中相关参数的影响.结果显示,当冷模温度足够慢地从900K下降到300K时,对应2.0×105～5.0×105W/(m2K)范围内的热传输指数,多定态现象发生.当多定态发生,冷模温度达到一个临界值时,固液界面上会产生剧烈的温度下降.随着该温度的突然下降,在液固界面上很可能会发生玻璃转变.

Multiple steady states during splat cooling studied by the bifurcation theory

A splat cooling process of alloy Pd82Si18 is modelled to analyze the effect of the heat transfer coefficient,which is difficult to determine experimentally,on solidification variables.It is shown that,multiple-steady-states phenomenon occurs for the heat transfer coefficient ranging from 2.0×105 W/(m2K) to 5.0×105 W/(m2K),when the temperature in the cold mould T0 decreases sufficiently slowly from 900 K to 300 K.There is an abrupt temperature drop,with which the glass transition might take place,at the liquid-solid interface,when T0 approaches a marginal value.