工艺参数对电磁冷坩埚定向凝固Nb-Si基合金固液界面的影响
|
摘要
采用电磁冷坩埚定向凝固技术研究了加热功率、抽拉速率和保温时间对Nb-22Ti-16Si-3Cr-3Al-2Hf(原子分数,%)合金固液界面的影响.采用正交实验制备合金试样.结果表明,延长保温时间、减小抽拉速率和提高加热功率有利于保持固液界面的宏观形态为平界面.随着抽拉速率的增加,初生Nb固溶体(Nbss)一次枝晶臂间距和二次枝晶臂间距逐渐减小;随着加热功率的增加,初生Nbss一次枝晶臂间距和二次枝晶臂间距逐渐增加;随着保温时间的延长,初生Nbss一次枝晶臂间距和二次枝晶臂间距先增大后减小.增大抽拉速率、减小加热功率和缩短保温时间有利于一次枝晶臂间距和二次枝晶臂间距的细化.
Nb-Si base alloys have attracted considerable attentions as the potential high temperature structural materials working in the service temperature range of 1200~1400 ℃ because of their high melting points(>1750 ℃),moderate densities(6.6~7.2 g/cm3) and excellent high temperature strength.However,the mismatching between room temperature fracture toughness and high temperature strength has limited their practical applications.Directional solidification(DS) and alloying have been proved to be the effective methods to overcome this critical issue.The DS processes used to prepare Nb-Si base alloys included Czochralski directional solidification in a copper crucible,electron beam directional solidification,optical floating zone melting,integrally directional solidification and electromagnetic cold crucible directional solidification(ECCDS).The previous studies focused on the effect of process parameters on microstructure and mechanical properties in the steady-state growth region(SSGR).However,the microstructure in the SSGR was controlled by the solid-liquid interface,and the solid-liquid interface was controlled by process parameters.Therefore,the study about the effect of process parameters on solidliquid interface was very important.In this work,the master alloy with the nominal composition of Nb-22Ti-16Si-3Cr-3Al-2Hf(atomic fraction,%) was prepared by vaccum non-consumable arc-melting first,and then induction skull melting.The DS experiments were performed in the ECCDS device equipped with a square water cooled copper crucible(internal dimension:26 mm×26 mm×120 mm) and a Ga-In alloy pool.There were three processing parameters in ECCDS including heating power of power supply,withdrawal rate and holding time.The DS ingots were prepared according to the orthogonal test(L9(33)).Instability degree was defined as the ratio of the height of solid-liquid interface to the width of the DS ingot.The results showed that there were three macroscopic morphologies of solid-liquid interfaces;the increase of holding time,decrease of withdrawal rate and elevation of heating power were conducive to keeping the solid-liquid interface macroscopic morphology planar.With the increase of withdrawal rate,primary dendrite arm spacing(d1) and secondary dendrite arm spacing(d2) decreased gradually;with the increase of heating power,d1 and d2increased gradually;with the increase of holding time,d1 and d2increased first and then decreased.The higher withdrawal rate,lower heating power and less holding time were beneficial to refining the d1 and d2.
Nb-Si base alloys have attracted considerable attentions as the potential high temperature structural materials working in the service temperature range of 1200~1400 ℃ because of their high melting points(>1750 ℃),moderate densities(6.6~7.2 g/cm3) and excellent high temperature strength.However,the mismatching between room temperature fracture toughness and high temperature strength has limited their practical applications.Directional solidification(DS) and alloying have been proved to be the effective methods to overcome this critical issue.The DS processes used to prepare Nb-Si base alloys included Czochralski directional solidification in a copper crucible,electron beam directional solidification,optical floating zone melting,integrally directional solidification and electromagnetic cold crucible directional solidification(ECCDS).The previous studies focused on the effect of process parameters on microstructure and mechanical properties in the steady-state growth region(SSGR).However,the microstructure in the SSGR was controlled by the solid-liquid interface,and the solid-liquid interface was controlled by process parameters.Therefore,the study about the effect of process parameters on solidliquid interface was very important.In this work,the master alloy with the nominal composition of Nb-22Ti-16Si-3Cr-3Al-2Hf(atomic fraction,%) was prepared by vaccum non-consumable arc-melting first,and then induction skull melting.The DS experiments were performed in the ECCDS device equipped with a square water cooled copper crucible(internal dimension:26 mm×26 mm×120 mm) and a Ga-In alloy pool.There were three processing parameters in ECCDS including heating power of power supply,withdrawal rate and holding time.The DS ingots were prepared according to the orthogonal test(L9(33)).Instability degree was defined as the ratio of the height of solid-liquid interface to the width of the DS ingot.The results showed that there were three macroscopic morphologies of solid-liquid interfaces;the increase of holding time,decrease of withdrawal rate and elevation of heating power were conducive to keeping the solid-liquid interface macroscopic morphology planar.With the increase of withdrawal rate,primary dendrite arm spacing(d1) and secondary dendrite arm spacing(d2) decreased gradually;with the increase of heating power,d1 and d2increased gradually;with the increase of holding time,d1 and d2increased first and then decreased.The higher withdrawal rate,lower heating power and less holding time were beneficial to refining the d1 and d2.
引文
[1]Bewlay B P,Jackson M R,Zhao J C,Subramanian P R,Mendiratta M G,Lewandowski J J.MRS Bull,2003;28:646
[2]Bewlay B P,Jackson M R,Zhao J C,Subramanian P R.Metall Mater Trans,2003;34A:2043
[3]Subramanian P,Mendiratta M,Dimiduk D.JOM,1996;48:33
[4]Bewlay B P,Jackson M R,Lipsitt H A.Metall Mater Trans,1996;27A:3801
[5]Mendiratta M G,Lewandowski J J,Dimiduk D M.Metall Trans,1991;22:1573
[6]Li Y L,Ma C L,Zhang H,Miura S.Mater Sci Eng,2011;A528:5772
[7]Tian Y X,Guo J T,Cheng G M,Sheng L Y,Zhou L Z,He L L,Ye H Q.Mater Des,2009;30:2274
[8]Sekido N,Kimura Y,Miura S,Wei F G,Mishima Y.J Alloys Compd,2006;425:223
[9]Sha J B,Hirai H,Tabaru T,Kitahara A,Ueno H,Hanada S.Metall Mater Trans,2003;34A:85
[10]Bewlay B P,Jackson M R,Lipsitt H A.J Phase Equilib,1997;18:264
[11]Guan P,Guo X P,Ding X,Zhang J,Gao L,Kusabiraki K.Acta Metall Sin(Engl Lett),2004;17:450
[12]Guo X P,Gao L M.J Aeron Mater,2006;26(3):47(郭喜平,高丽梅.航空材料学报,2006;26(3):47)
[13]Kang Y W.PhD Dissertation,Beijing Institute of Aeronautical Materials,2008(康永旺.北京航空材料研究院博士学位论文,2008)
[14]Wu M L,Wang Y Y,Li S S,Jiang L W,Han Y F.Int J Mod Phys,2010;24B:2964
[15]Kim W Y,Tanaka H,Kasama A,Hanada S.Intermetallics,2001;9:827
[16]Sekito Y,Miura S,Ohkubo K,Mohri T,Sakaguchi N,Watanabe S,Kimura Y,Mishima Y.Mater Res Soc Symp Proc,2009;1128:38
[17]Guo H S,Guo X P.Scr Mater,2011;64:637
[18]Yao C F,Guo X P,Guo H S.Acta Metall Sin,2008;44:579(姚成方,郭喜平,郭海生.金属学报,2008;44:579)
[19]He Y S,Guo X P,Guo H S,Sun Z P.Acta Metall Sin,2009;45:1035(何永胜,郭喜平,郭海生,孙志平.金属学报,2009;45:1035)
[20]Wang Y,Guo X P.Acta Metall Sin,2010;46:506(王勇,郭喜平.金属学报,2010;46:506)
[21]Yan Y C,Ding H S,Kang Y W,Song J X.Mater Des,2014;55:450
[22]Yan Y C,Ding H S,Song J X.Proc Eng,2012;27:1033
[23]Nie G,Ding H S,Chen R R,Guo J J,Fu H Z.Mater Des,2012;39:350
[24]Ding H S,Nie G,Chen R R,Guo J J,Fu H Z.Mater Des,2012;41:108
[25]Li Y Y,Hu C R.Experiment Design and Data Processing.2nd Ed.,Beijing:Chemical Industry Press,2008:124(李云雁,胡传荣.试验设计与数据处理.第二版,北京:化学工业出版社,2008:124)
[26]Wang Y L,Guo J J,Fu H Z.J Harbin Inst Technol,2008;40:1808(王艳丽,郭景杰,傅恒志.哈尔滨工业大学学报,2008;40:1808)
[27]Zhou Y H,Hu Z Q,Jie W Q.Solidification Technology.Beijing:Machinery Industry Press,1998:155(周尧和,胡壮麒,介万齐.凝固技术.北京:机械工业出版社,1998:155)
[28]Hu H Q.Metal Solidification Principle.2nd Ed.,Beijing:Machinery Industry Press,2007:108(胡汉起.金属凝固原理.第二版,北京:机械工业出版社,2007:108)
[2]Bewlay B P,Jackson M R,Zhao J C,Subramanian P R.Metall Mater Trans,2003;34A:2043
[3]Subramanian P,Mendiratta M,Dimiduk D.JOM,1996;48:33
[4]Bewlay B P,Jackson M R,Lipsitt H A.Metall Mater Trans,1996;27A:3801
[5]Mendiratta M G,Lewandowski J J,Dimiduk D M.Metall Trans,1991;22:1573
[6]Li Y L,Ma C L,Zhang H,Miura S.Mater Sci Eng,2011;A528:5772
[7]Tian Y X,Guo J T,Cheng G M,Sheng L Y,Zhou L Z,He L L,Ye H Q.Mater Des,2009;30:2274
[8]Sekido N,Kimura Y,Miura S,Wei F G,Mishima Y.J Alloys Compd,2006;425:223
[9]Sha J B,Hirai H,Tabaru T,Kitahara A,Ueno H,Hanada S.Metall Mater Trans,2003;34A:85
[10]Bewlay B P,Jackson M R,Lipsitt H A.J Phase Equilib,1997;18:264
[11]Guan P,Guo X P,Ding X,Zhang J,Gao L,Kusabiraki K.Acta Metall Sin(Engl Lett),2004;17:450
[12]Guo X P,Gao L M.J Aeron Mater,2006;26(3):47(郭喜平,高丽梅.航空材料学报,2006;26(3):47)
[13]Kang Y W.PhD Dissertation,Beijing Institute of Aeronautical Materials,2008(康永旺.北京航空材料研究院博士学位论文,2008)
[14]Wu M L,Wang Y Y,Li S S,Jiang L W,Han Y F.Int J Mod Phys,2010;24B:2964
[15]Kim W Y,Tanaka H,Kasama A,Hanada S.Intermetallics,2001;9:827
[16]Sekito Y,Miura S,Ohkubo K,Mohri T,Sakaguchi N,Watanabe S,Kimura Y,Mishima Y.Mater Res Soc Symp Proc,2009;1128:38
[17]Guo H S,Guo X P.Scr Mater,2011;64:637
[18]Yao C F,Guo X P,Guo H S.Acta Metall Sin,2008;44:579(姚成方,郭喜平,郭海生.金属学报,2008;44:579)
[19]He Y S,Guo X P,Guo H S,Sun Z P.Acta Metall Sin,2009;45:1035(何永胜,郭喜平,郭海生,孙志平.金属学报,2009;45:1035)
[20]Wang Y,Guo X P.Acta Metall Sin,2010;46:506(王勇,郭喜平.金属学报,2010;46:506)
[21]Yan Y C,Ding H S,Kang Y W,Song J X.Mater Des,2014;55:450
[22]Yan Y C,Ding H S,Song J X.Proc Eng,2012;27:1033
[23]Nie G,Ding H S,Chen R R,Guo J J,Fu H Z.Mater Des,2012;39:350
[24]Ding H S,Nie G,Chen R R,Guo J J,Fu H Z.Mater Des,2012;41:108
[25]Li Y Y,Hu C R.Experiment Design and Data Processing.2nd Ed.,Beijing:Chemical Industry Press,2008:124(李云雁,胡传荣.试验设计与数据处理.第二版,北京:化学工业出版社,2008:124)
[26]Wang Y L,Guo J J,Fu H Z.J Harbin Inst Technol,2008;40:1808(王艳丽,郭景杰,傅恒志.哈尔滨工业大学学报,2008;40:1808)
[27]Zhou Y H,Hu Z Q,Jie W Q.Solidification Technology.Beijing:Machinery Industry Press,1998:155(周尧和,胡壮麒,介万齐.凝固技术.北京:机械工业出版社,1998:155)
[28]Hu H Q.Metal Solidification Principle.2nd Ed.,Beijing:Machinery Industry Press,2007:108(胡汉起.金属凝固原理.第二版,北京:机械工业出版社,2007:108)