1.With the increase of the cooling rate, both the grain size and secondary dendrite arm spacing of A357 alloy decrease, and the distribution of Si phase is changed from a chain to a short strip or short bar.
2.After the structure analasis of powders at different milling time,it showed that nanocrystal α Fe(Si)Solid solution(bcc)was formed during the milling of Fe 75 si 25 powders,the lattice spacing and grain size of α Fe(Si)decreased with increase of milling time.
3.1. The mechanical property were achieved with as roll CrNb (0.75%C) rail steel: Gb-l O65MPa, 6~=1 0.5%, ak(20C) =1 3.3J/cm2,K1c(-20 t)33.OMPam? , the pearlite interlamellar spacing is to 0.1895pm, seven grade size of austenite grain is determined.
