| 摘要 |
Controlling the grain refinement of aluminium (Al) alloys comprises: (i) calibrating the grain sizes for different values of the grain growth index (GGI), for the casting process used, represented by formula (I); determining the GGI value for the particular aluminium base material by using the above formula; (iii) using the calibration data obtained in (i) to calculate the grain size of the aluminium base material and how the concentration of grain size affecting agents in the aluminium melt should be changed in order to obtain an aluminium casting having a desired crystal grain size; and (iv) adding the amount of grain size affecting agents calculated in (iii) to the melt. GGI = ~E miCi(ki-1) = m1C1(k1-1) + m2C2(k2-1) + .... (I) In (I): mi is the slope of the liquidus in the binary (Al-i) system; Ci is the concentration of its dissolved solute in the alloy; ki is the distribution coefficient of solute i between solid and liquid; and m1, C1 and k1, etc. represent the corresponding values for each alloy constituent. |
