上海交通大学：《材料加工原理 Principles of Materials Processing》教学资源（课件讲稿）凝固和铸造 Solidification and casting_Solidification of multi phase alloys（1）

先进材料疑固实验室 Laboratory of Advanced Materials Solidification 1896 1920 1987 2006 Solidification of multi phase alloys(1) Dr.Mingxu Xia anced Mate 国 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY

1896 1920 1987 2006 Solidification of multi phase alloys (1) Dr. Mingxu Xia

先进材料疑固实验室 References Laboratory of Advanced Materials Solidification M.C.Flemings,凝固过程 W.Kurz,凝固原理 ©介万奇，凝固技术 A0V800 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY

References M.C.Flemings, 凝固过程 W.Kurz,凝固原理 介万奇，凝固技术

先进材料疑固实验室 OUTLINE Laboratory of Advanced Materials Solidification Solidification of Eutectics Coupled eutectic growth morphology Other eutectic morphologies Jackson-Hunt model for Regular eutectics Morphology control method for regular eutectics Model for irregular eutectics Competitive growth of eutectic and dendritic phases Coupled zone in binary alloy phase diagram Solidification of Peritectics Microstructure control through solidification method 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY

OUTLINE Solidification of Eutectics • Coupled eutectic growth morphology • Other eutectic morphologies • Jackson-Hunt model for Regular eutectics • Morphology control method for regular eutectics • Model for irregular eutectics • Competitive growth of eutectic and dendritic phases • Coupled zone in binary alloy phase diagram Solidification of Peritectics Microstructure control through solidification method

先进材料疑固实验室 Review Laboratory of Advanced Materials Solidification (1+2 maximum syntectic 2 peritectic 2+3 peritectic minimum monotectic E eutectic 7 a eutectoid peritectoid spinodal 6 1+a2 A Mole fraction B Fig.3.15 A hypothetical diagram displaying an array of possible invariant reac- tions in a binary alloy system.(After Rhines [5]). 上游充通大学 SHANGHAI JIAO TONG UNIVERSITY

Review

先进材料疑固实验室 Review Laboratory of Advanced Materials Solidification -Il Eutectic,Ill Hypoeutectic,IV Hypereutectic I1 N 400 A327.5 L 300 IL+8 231.9B 2 L+a 200- M 183 N 19 2 61.92 97.5 B 3 100 a+8 Pb 20 40 60 80 Sn W(%) Single Multi e Pure metal phase Phase(eutectics) 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY

Review －II Eutectic, III Hypoeutectic, IV Hypereutectic Pure metal Single phase Multi Phase (eutectics)

先进材料疑固实验室 Coupled eutectic morphology Laboratory of Advanced Materials Solidification liquid ainjejadway a+liquid 0+ liquid a+0 0% weight copper 33% 60% 10um Part of Al-Cu phase diagram Solidified microstructure of Al-33wt%Cu alloy (http://www.southampton.ac.uk/-pasr1/al-cu.htm) 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY

Coupled eutectic morphology Part of Al-Cu phase diagram Solidified microstructure of Al-33wt%Cu alloy (http://www.southampton.ac.uk/~pasr1/al-cu.htm)

先进材料疑固实验室 Review Laboratory of Advanced Materials Solidification Eutectic solidification is the solidification of a liquid with eutectic composition. During eutectic solidification,two solid phases nucleate and then grow simultaneously. Eutectic solidification results in formation of eutectic structure. anced Matera 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY

Review Eutectic solidification is the solidification of a liquid with eutectic composition. During eutectic solidification, two solid phases nucleate and then grow simultaneously. Eutectic solidification results in formation of eutectic structure

先进材料疑固实验室 Review Laboratory of Advanced Materials Solidification LIQUID a 个E CL.T"y SOLID a、 SOLID B2 A CaM Ca CE C Sa Sβ COMPOSITION (PERCENT B) y (a) (b) FIGURE 4-2 Undercoolings and interface liquid composition Cof a eutectic alloy at a point on the interface in front of the a phase.(a)Phase diagram;(b)interface showing point yi for which construction of (a)applies. 熟 上游文通大学 SHANGHAI JIAO TONG UNIVERSITY

Review

先进材料疑固实验室 Coupled eutectic morphology Laboratory of Advanced Materials Solidification Due to their excellent castability and often good composite properties,many casting alloys have compositions same as or close to eutectic compositions with various microstructure. ory ot anced Materd 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY

Coupled eutectic morphology Due to their excellent castability and often good composite properties, many casting alloys have compositions same as or close to eutectic compositions with various microstructure

先进材料疑固实验室 Coupled eutectic morphology Laboratory of Advanced Materials Solidification ⊕ Materials for which AS/R>2 usually have a large anisotropy in S/L interfacial energy and are therefore faceted,whereas for which AS /R<2 are non-faceted.The various combinations of such materials lead to different morphologies for the eutectic structure. The eutectic microstructure is also effected by the volume fractions of the two phase. 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY

Coupled eutectic morphology Materials for which ΔSm f /R>2 usually have a large anisotropy in S/L interfacial energy and are therefore faceted, whereas for which ΔSm f /R<2 are non-faceted. The various combinations of such materials lead to different morphologies for the eutectic structure. The eutectic microstructure is also effected by the volume fractions of the two phase