An investigation of single-phased metallic solidification process using high-temperature confocal laser scanning microscope combined with differential scanning colorimetry  

作　　者：Xing-zhi Zhou De-yong Wang Tian-peng Qu Dong Hou Shao-yan Hu Jun Tian Xiang-long Li Lei Fan Zhi-xiao Zhang 

机构地区：[1]School of Iron and Steel,Soochow University,Suzhou,215021,Jiangsu,China

出　　处：《Journal of Iron and Steel Research International》2025年第2期437-451,共15页钢铁研究学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.52274339,52174321,52074186,and 52104337);Natural Science Foundation of Jiangsu Province(Grant No.BK20231317);China Baowu Low-Carbon Metallurgy Innovation Fund(Grant No.BWLCF202108).

摘　　要：To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates.

关 键 词：NUCLEATION Metallic solidification process Differential scanning colorimetry High-temperature confocal laser scanning microscope Interfacial wetting-lattice mismatch heterogeneous nucleation model 

分 类 号：TG1[金属学及工艺—金属学]