EFFECT OF HOMOGENIZATION TREATMENT UNDER AN ELECTRIC FIELD ON T_1 DISTRIBUTION AND MECHANICAL PROPERTIES OF 2091 Al－Li ALLOY

ＥＦＦＥＣＴＯＦＨＯＭＯＧＥＮＩＺＡＴＩＯＮＴＲＥＡＴＭＥＮＴＵＮＤＥＲＡＮＥＬＥＣＴＲＩＣＦＩＥＬＤＯＮＴ_１ＤＩＳＴＲＩＢＵＴＩＯＮＡＮＤＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦ２０９１Ａｌ－ＬｉＡＬＬＯＹ￥ＬＩＵＷｅｉ;ＣＵＩＪｉａｎｚｈｏ?..     

SOLIDIFICATION BEHAVIOR AND MICROSTRUCTURE EVOLUTION OF Si BEARING TiAl ALLOY

１　ＩＮＴＲＯＤＵＣＴＩＯＮＴｉＡｌａｌｌｏｙｓｈａｖｅｂｅｅｎｒｅｃｅｉｖｉｎｇａｎｉｎｃｒｅａｓｉｎｇａｔｔｅｎｔｉｏｎｂｅｃａｕｓｅｏｆｔｈｅｉｒｈｉｇｈｓｐｅｃｉｆｉｃｓｔｒｅｎｇｔｈ，ｅｘｃｅｌｌｅｎｔｓｔｉｆｆｎｅｓｓ，ｇｏｏｄｏｘｉｄａｔｉｏｎｒｅｓｉｓｔａｎｃｅ，ａｎｄｃｒｅｅｐｒｅｓｉｓｔａｎｃｅ［１－３］．Ｈｏｗｅｖｅｒ，ｔｈｅｓｅａｌｌｏｙｓｓｕｆｆｅｒｆｒｏｍａｌｏｗｄｕｃｔｉｌｉｔｙｕｐｔｏａｂｏｕｔ６００℃．Ｅｘｔｅｎｓｉｖｅｉｎｖｅｓｔｉｇａｔｉｏｎｏｆａｌｌｏ…     

INFLUENCE OF HOMOGENIZATION TREATMENT UNDER AN ELECTRIC FIELD ON DUCTILITY OF 2091 Al－Li ALLOY DURING HOT ROLLING

ＩＮＦＬＵＥＮＣＥＯＦＨＯＭＯＧＥＮＩＺＡＴＩＯＮＴＲＥＡＴＭＥＮＴＵＮＤＥＲＡＮＥＬＥＣＴＲＩＣＦＩＥＬＤＯＮＤＵＣＴＩＬＩＴＹＯＦ２０９１Ａｌ－ＬｉＡＬＬＯＹＤＵＲＩＮＧＨＯＴＲＯＬＬＩＮＧ￥ＬＩＵＷｅｉ;ＣＵＩＪｉａｎｚｈｏｎｇ（Ｎｏｒｔｈｅａ...     

NUMERICAL SIMULATION OF ALLOY SOLIDIFICATION BY A TWO－PHASE MODEL

本文介绍了合金凝固传输过程中的二相流数学模型．该模型描述了固－液界面的传输现象和液相对流对宏观偏析的影响，并考虑了生核过程，热和溶质的过冷效应，及固相颗粒的宏观运动，从而把宏观传输过程和微观结构结合起来．采用该模型，对Ａｌ－４％Ｃｕ等轴晶合金的凝固进行了完整的数值模拟．     

INTERFACE MORPHOLOGIES AND SOLUTE SEGREGATION OF Al-Li ALLOY 8090 DURING UNIDIRECTIONAL SOLIDIFICATION

The solid-liquid interface morphology and solute segregation behaviour of AI-Li alloy 8090during unidirectional solidification were studied by the liquid metal quenehing method undervaried processing conditions.When solidification rate,RO.75 mm/min (temper-ature gradient,G_L=130℃/cm),the structure revealed of planar or dendritic interfacerespectively.With the increase of R,the interface morphology becomes cellular from planargradually,within a narrow range.And the greater the R,the,finer the dendrite.Segregationof element Cu and impurity elements Fe and Si are quite severe,the interface morphologymarkedly influences on solute segregation.During solidification at coarse dendrite interface,their segregation ratios are rather great and solidified structure is coarse.     

HARDENING OF RAPID SOLIDIFICATION Al－Fe－V－Si ALLOY EXPOSED AT ELEVATED TEMPERATURE

ＨＡＲＤＥＮＩＮＧＯＦＲＡＰＩＤＳＯＬＩＤＩＦＩＣＡＴＩＯＮＡｌ－Ｆｅ－Ｖ－ＳｉＡＬＬＯＹＥＸＰＯＳＥＤＡＴＥＬＥＶＡＴＥＤＴＥＭＰＥＲＡＴＵＲＥ￥ＸｕＹｉｈｅｎｇ；ＬｏｎｇＣｈｕｎｇｕａｎｇ；ＬｉＳｏｎｇｒｕｉ；ＬｉＷｅｎｘｉａｎ；ＹａｎｇＳｈｉｂ...     

EFFECTS OF Zn CONCENTRATION ON WETTABILITY OF Sn-Zn ALLOY ON Cu AND ON THE INTERFACIAL MICROSTRUCTURE BETWEEN Sn-Zn ALLOY AND Cu

The potential of using a hypoeutectic, instead of eutectic, Sn-Zn alloy as a lead-free solder has been discussed. The nonequilibrium melting behaviors of a series of Sn-Zn alloys were examined by differential thermal analysis. It was found that at a heating rate of 5℃/min, Sn-6.SZn exhibited no melting range. Dipping and spreading tests were carried out to characterize the wettability of Sn-Zn alloys on Cu. Both tests exhibited that Sn-6.5Zn has significantly better wettability on Cu than Sn-9Zn. The reaction layers formed during the spreading tests were examined. When the Zn concentration fell between 2.5wt%-9wt%, two reaction layers were formed at the interface, a thick and flat Cu5Zn8 adjacent to Cu and a thin and irregular Cu-Zn-Sn layer adjacent to the alloy. Only a Cu0Sn5 layer was formed when the Zn concentration decreased to 0.5wt%. The total thickness of the reaction layer（s） between the alloy and Cu was found to increase linearly with the Zn concentration.     

EFFECT OF PHOSPHORUS ON SOLIDIFICATION,ELEMENT SEGREGATION AND η-PHASE PRECIPITATION IN GH 761 ALLOY

本文用金相、电子探针等方法研究了磷对ＧＨ７６１合金凝固过程、元素偏析及η相析出的影响。结果表明，随合金中磷含量升高，磷大量地偏析于枝晶间，强烈地降低合金的终凝温度，促进Ｔｉ，Ｎｉ等元素的偏析，抑制Ｍｏ，Ｂ，Ｓ，Ｓｉ等元素的偏析，磷显著地促进η相的析出，降低η相析出温度。     

THE INFLUENCES OF SOLUTION PH AND CURRENT DENSITY ON COERCIVITY OF ELECTROPLATING CoNdNiMnP PERMANENT MAGNETIC ALLOY FILM ARRAYS

1.IntroductionPermanent magnetic films, as an important type of functional films, have been widely used in vertical magnetic recording medium, magnetic field sensors, micro-actuators, optical insulators, optical switches,micropumps and scanners fields etc.[1-4]. Specially, with the development of micro electro-mechanical systems (MEMS), because of good resistance to bad environment and easily assembling, electromagnetic micro-actuators have been studied and fabricated by many researchers all …     

THE INFLUENCES OF SOLUTION PH AND CURRENT DENSITY ON COERCIVITY OF ELECTROPLATING CoNdNiMnP PERMANENT MAGNETIC ALLOY FTLM ARRAYS

The influences of plating bath solution PH and current density on coercivity of electroplating CoNdNiMnP permanent magnetic film arrays were studied. The experiment results show that both for solution PH and current density there were the best depositing parameters. Too high and too low plating bath solution PH or current density both result in decreasing of the film array coercivity. When solution PH is 3.5 and current density is 5mA/cm^2, the prepared film array coercivity can reach the maximum.     

磁场作用下Al-Pb偏晶合金的凝固过程

在恒定磁场作用下对Al-Pb合金进行定向凝固实验, 考察了合金成分、凝固速度、恒定磁场对凝固组织的影响. 模拟研究了恒定磁场作用下Al-Pb合金定向凝固组织的形成过程, 分析了磁场的影响机理和合金成分、凝固速度、磁场强度对弥散型凝固组织获得的影响. 模拟和实验均表明恒定磁场促进弥散型偏晶合金凝固组织的形成.     

恒定磁场作用下Al-Pb合金快速定向凝固

在恒定磁场作用下对Al-Pb合金进行了快速定向凝固实验,考察了磁场强度对凝固组织的影响,分析了磁场的作用机理.结果表明,恒定磁场能显著减弱熔体对流,提高凝固界面前沿液-液相变过程的空间均匀性,减缓液滴的碰撞凝并速度,使凝固试样中的弥散相粒子最大和平均尺寸减小,粒子尺寸分析布范围变窄,有助于获得弥散型偏晶合金凝固组织.     

直流磁场作用下Al-18Si合金的凝固行为

研究了在单独场源－直流磁场作用下,Ａｌ－１８Ｓｉ（质量分数．％）合金定向凝固时形成富Ｓｉ特殊表面的现象;直流磁场力对熔体无搅拌作用,其磁感应强度为０．２４Ｔ左右时,开始出现Ｓｉ的宏观偏析现象,且偏聚层厚度随磁感应强度的增大而增加;探讨了稳恒直流磁场对此合金微观组织形成规律的影响机理。     

Ring--Like Solidification Structure Of Mnbi Phase In Bi—Mn Alloy Under A High Magnetic Field

对强磁场作用下Bi-Mn合金分别从全熔态和从固液两相区开始的凝固过程及其组织的实验研究表明，磁场使初生MnBi相在试样外侧呈环状偏聚，其自身生长为棒状，棒的长轴沿磁场方向呈定向规则排列，而试样心部基本无初生MnBi相。在Curie点以上开始进行较慢的凝固时，由片状聚合而成的棒状MnBi具有单晶特征。对以上现象的形成原因进行了分析。     

激光快速凝固条件下Cu-27.3%Mn合金的微观组织特征

利用ＣＷ ＣＯ２激光器对Ｃｕ－２７．３％Ｍｎ进行了系列表面熔凝实验,对该合金的组织形态和胞晶间距选择规律进行了研究。结果表明;随着生长速度的提高,组织形态由低速平界面向细胞晶和高速绝对稳定平界面转变。     

CELLULAR SPACING SELECTION OF Al-0.53wt%Zn ALLOY UNDER NEAR-RAPID DIRECTIONAL SOLIDIFICATION CONDITION

1.IntroductionCellular/dendriticspacing,asoneofthemostimportantsolidificationmicrostructuralscales,isofcriticalsignificancetothestudyofsolidificationtheoryandcontrolofmicrostructures.Recently,severalimportantdevelopments[1--4]havebeenmadeintheoreticalresearchesonplanarfrontgrowthandtheselectionofcellular/dendriticstructureatlowgrowthvelocityunderconstrainedcrystalgrowthcondition,andithasbeenrecognizedinexperimentalinvestigationsls--ic]thatthereexistsawideallowablerangeofprimarydendriticspacing…     

Al—0.53Zn合金近快速定向凝固条件下的胞晶间距选择

利用Ｂｒｉｄｇｍａｎ装置考察了Ａｌ－０．５３Ｚｎ单相合金在近快速定向凝固条件下的胞晶间距选择规律。结果表明：在给定的温度梯度下,随着生长速度的增大,定向凝固组织均为胞状晶、胞晶间距λ的分布存在一个较宽范围,其最大,最小及平均间距随生长速度ｖ变化的实验规律可为：λｍａｘ＝９４８．５１ｖ＾－０．４９６１,λｍｉｎ＝６６１．１６ｖ＾－０．５０１５,λ＾－＝４１２．４１ｖ＾－０．５０４９。ＫＧＴ理论模型较     

MICROSTRUCTURAL FEATURE OF Al-In MONOTECTIC ALLOY PROCESSED UNDER MICROGRAVITY

The microstructural feature of Al-In monotectic alloy processed under microgravity has beeninvestigated It was found that in the sample cooled in space,there are a lot of In particles inA! dendrite,but no particle has been observed in the sample cooled on the ground.Moreover,the In particles distribute with regularity and the A1 dendrite has an obvious boundary layermarked by a string of particles.Thus,the distinction between them may reflect the character-istics of the solid/liquid interface during solidification under different gravity conditions.     

液态金属铝及其凝固过程的微观结构转变特性

采用分子动力学方法对液态金属Ａ１及其凝固过程中的微观结构转变特性进行了模拟研究，发现在１８００～３５０Ｋ的温度区间内，对全局结构组态起重要作用的ＨＡ键型组态有１５５１、１５４１、１４３１、１３１１、１３２１和１４２２等，其中以１５５１键型组态最为显著，它在全过程的微观结构转变中起着主导作用，是其双体分布函数ｇ（ｒ）曲线的第二峰出现由光滑正弦峰平台分裂为二个次峰的转变过程的决定性因素     

高密度脉冲电流对A356铝合金低温熔体凝固组织的影响

研究了高密度脉冲电流的A356铝合金低温熔体凝固组织的影响。实验中对680和630℃的低温熔体施加脉冲电流处理。对比试验和凝固曲线测试结果表明。低温熔体中施加脉冲电流有利于增大凝固过冷度，提高冷却速率。缩短凝固时间。细化凝固组织。同时，经脉冲电流处理后，随熔体的保温时间延长。凝固组织逐渐粗化。分析认为，低温熔体结构比凝固过程本身更能影响最终凝固组织。