過共析鋼在過冷奧氏體形變過程中的組織超細化_圖文

1、224Vol.22No.4 20088CHINESE JOURNAL OF MATERIALS RESEARCH August200811 211.1000832.100083Gleeble1500,.:,(+.,;,.,TG142.11005-3093(200804-0374-05 Ultra-renement of hypereutectoid steel during deformationof undercooled austeniteCHEN Wei1LI Longfei1YANG Wangyue2SUN Zuqing11.The State Key Laboratory for A

2、dvanced Metals and Materials,University of Science and Technology Beijing,Beijing1000832.School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing100083*Supported by National Natural Science Foundation of China No.50471092and Specialized Research Fund for the D

3、octoral Program of National Education Ministry No.20050008017.Manuscript received August10,2007;in revised form January23,2007.*To whom correspondence should be addressed,Tel:(01062334919,Email:wyyang ABSTRACT The microstructure evolution of a hypereutectoid steel(0.97%Cduring deformation of underco

4、oled austenite was investigated by uniaxial hot compression simulation experiment.The results indicate that the proeutectoid network carbides were restrained by deformation of undercooled austenite and only pearlite was formed by dynamic transformation of undercooled austenite.Lamellar pearlite was

5、spheroidized dynamically by hot deformation,resulting in the formation of ultrane(+microduplex microstructures.The increase of deformation temperature,leading to the decrease of the degree of un-dercooling,has the retarding eect on dynamic transformation of undercooled austenite.The decrease of stra

6、in rate,leading to the prolonging of the deformation time,was benecial to dynamic transformation of undercooled austentite and dynamic spheroidization of pearlite,but the resulted ultrane microduplex microstructures was coarser.KEY WORDS metallic materials,hypereutectoid steel,undercooled austenite,

7、cementite,ultra-renement(>0.77%,.Sherby19Maki1012,(HWW34(IWW5*5047109220050008017.2007810;2008123.: ,(HWW+DET67(HWW+DETWAD891012,(0.51.0m(0.10.5m.,37,.,(T10A cmA rcm(4:375,.1T10,( ,%:C0.97,Si0.26,Mn0.31,S0.004,P 0.0056.ThermoCalc A cm A1816730,Gleeble150030/s A rcm A r1600 560.Gleeble1500,6mm15mm

8、.20/s10005min, 30/s(650700,0.1s10.01s1.,.,.ZEISSSUPRA55.SEM ImageTool,.TEM H800,2030,5%HClO4+95%CH3CH2OH,75V.2,(1a, 3.5%.20/s10005min,30/s6505min,(1b.6500.1s1,(2a,(2b,.:,;,FeC13(,., 1(a,(b30/s6505minFig.1Microstructure of the hypereutectoid steel(afurnace cooling,(bIsothermal5min at650 by cooling ra

9、te of30 /s2650,0.1s1,=0.11(a,(bFig.2Microstructure of the hypereutectoid steel deformed at650at0.1s1to strain of0.11(a dynamic pearlite transformation,(bthe grain boundaries of prior austenite376223650,0.1s 1(a=0.92,(b=1.61Fig.3Microstructure of the hypereutectoid steel deformed at 650at 0.1s 1to st

10、rain of (a=0.92(b=1.61 4650,0.1s 1,=1.61TEM(a(bFig.4TEM photo of the hypereutectoid steel deformed at 650at 0.1s 1to strain of 1.61(aandthe distribution of cementite particle sizes (b,.=0.92(3a,.=1.61,(3b.TEM,(4a,0.61±0.19m,(4b,0.25±0.10m,0.07±0.03m.GibbsThomson,14.,15.,.,.,14.,.,.,.,

11、Cottrell,.,4:3775Fig.5Inuence of deformation parameters on trans-formation kinetics of undercooled austenite ofthe hypereutectoid steel6650,0.01s1,=1.61(a(b Fig.6Microstructure of the hypereutectoid steel de-formed at650,at0.01s1to strain of1.61(aand the distribution of cementite particlesizes(b,16,

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