PHASE TRANSFORMATION AND CHARACTERISTICS IN FRECKLE AREAS FOR INCONEL 625 SUPERALLOY

The freckle formation and their phase characterizatics in freckle areas were investigated by means of microstructure analysis approaches and a thermodynamic equilibrium phase calculation method in an lnconel 625 alloy. These results show that in freckle areas a large number of M6C, MC, Laves and 8 phases precipitate in grain boundaries even within grain due to the enrichment and segregation of Mo and Nb during solidification, which results in almost of these freckle areas covered by these complex precipitated phases and induces small grains in freckle areas. Equilibrium phase and liquid segregation calculation can give a reasonable interpretation of the freckle feature for this alloy.     

快速凝固Al─3．18Ti─0．65C合金中TiC相的形成和分布特征

采用快速凝固技术在Ａｌ─３．１８Ｔｉ─０．６５Ｃ（ｗｔ─％）合金中获得了呈弥散分布的单一ＴｉＣ相颗粒，尺寸为３０─１００ｎｍ，原子组成为ＴｉＣ＿（０．７６）．结合常规和快速凝固组织的分析对比，并以热力学分析为基础。研究和探讨了ＴｉＣ相的形成过程和机制     

合金相结构因子和界面结合因子的计算方法及其在合金设计中的应用

以固体与分子经验电子理论（EET）和改进的Thomas－Fermi－Dirac（TFD）理论为基础,以合金奥氏体、合金马氏体及其界面为例,给出了相结构因子nA,F,S和界面结合因子ρ,Δρ,σ的计算方法计算了常用合金元素在0．2％C和1．0％C钢中的相结构因子和界面结合因子用相结构因子和界面结合因子阐述了强韧性良好的20CrNi3钢和20Cr2Ni4钢的强韧化机制和耐磨性极高的ZGMn13耐磨钢的耐磨机制,并用相结构因子和界面结合因子预言了一种强韧性更高的Cr－Ni－W－V－0．2％C钢,结果与实际符合良好．     

FORMATION OF SILICONIZED LAYER ON TiAI-BASED ALLOY AND THE OXIDATION RESISTANCE

The Ti-48Al alloy was pack siliconized with 15%Si+85%Al2O3. The microstructure of the siliconized coating on the TiAl-based alloy was analyzed and its effect on oxidation resistance was investigated. The specimens before and after cycle oxidation were examined by XRD and SEM equipped with XEDS. The results showed that the coating is composed of a thin Al2O3 outer layer and a composite inner layer of Ti5Si3 with an appropriate amount of Al2O3 dispersed in. Cycle oxidation tests showed that the high temperature oxidation resistance of TiAl-based alloy was greatly improved by forming such composite coating. No spaliation and crack happened and the weight gain was very small after cycle oxidation at 900℃ for 314h.     

提高W—Ni—Cu合金膨胀系数等性能的实例分析

为提高ＷＮｉＣｕ合金的膨胀系数等性能，提出了选择添加元素的原则，进行了金属Ｍｎ、Ａｇ粉末对ＷＮｉＣｕ合金性能影响的研究；并分析、讨论了影响ＷＮｉＣｕ合金性能的因素及研制具有良好综合性能的钨合金的可能途径     

EFFECT OF IRON ON FORMATION OF MECHANICALLY ALLOYED NiAl ALLOY AND ITS MECHANICAL PROPERTIES

ＥＦＦＥＣＴＯＦＩＲＯＮＯＮＦＯＲＭＡＴＩＯＮＯＦＭＥＣＨＡＮＩＣＡＬＬＹＡＬＬＯＹＥＤＮｉＡｌＡＬＬＯＹＡＮＤＩＴＳＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＪ．Ｔ．Ｇｕｏ;Ｌ．Ｚ．Ｚｈｏｕ;Ｚ．Ｇ．ＬｉｕａｎｄＷ．Ｍ．Ｙｉｎ（Ｉｎｓｔｉｔｎｔｅｏｆ...     

快速凝固Al─Fe基合金条带中准晶相的形成及稳定性

对快速凝固Ａｌ─Ｆｅ基合金的原始条带及退火组织进行了透射电镜分析．结果表明．原始条带截面组织按准晶形成可分成三个区域：无准晶区；准晶形成区；准晶分解区，在６９８Ｋ保温１ｈ发现中间区的准晶开始晶化．组织形貌类同铸态组织的准晶分解区，说明准晶的晶化是在凝固过程中进行的、并且始于准晶与基体界面处     

低合金Cr-Mo-V钢中VC沉淀相的精细结构

采用透镜电子显微分析（ＴＥＭ）的高分辨透射电子显微分析（ＨＲＥＭ）技术研究了低合金Ｃｒ－Ｍｏ－Ｖ铜不同回火温度下ＶＣ深淀相质点和精细结构及其与基体和界面关系,结果表明：较低温度回火时,ＶＣ沉淀相系以｛１００｝ａ为惯习面的纳米尺度的薄片,与基体存在Ｂａｋｅｒ－Ｎｕｔｔｉｎｇ关系,随着回火温度升高,片状相聚集成碳化物团或者发生球化,与基化丧失共格或部分共格,。     

STRUCTURE FORMATION OF UNDERCOOLED Fe-30Ni ALLOY

1. IntroductionFine grained structures generally have weakened microsegregation, reduced anisotropyand improved mechanical properties etc., so great interest hajs been focused on the grainrefinement occurring in single phase alloys undercooled beyond a critical value aT* since itwas first observed in 195911). Several attempts have been made to explain this phenomenon.Some ones attributed it to the copious nucleation during solidification[1--3], while the othersthought that the refined grains i…     

Cu-Zr-Nb系铜基块体非晶合金的形成

Cu8Zr3和Cu10Zr7相中存在Cu8Zr5和Cu6Zr5团簇结构,它们与Cu-Zr系的两个深共晶点Cu61.8Zr38.2和Cu56Zr44对应. Cu64Zr36是Cu-Zr二元系具有最大玻璃形成能力的成分点.依据形成块体非晶的＂变电子浓度线判据＂,以Cu64Zr36,Cu61.8Zr38.2和Cu56Zr44 3个二元成分为出发点,以Nb元素为第三组元,建立变电子浓度线（Cu64Zr36）100-xNbx,（Cu61.8Zr38.2）100-xNbx和（Cu56Zr44）100-xNbx.采用分步熔炼法,由铜模吸铸法制备直径为3 mm的合金棒.块体非晶的玻璃形成区及玻璃形成能力由XRD和热分析确定.结果表明,添加少量Nb（原子分数,x≤3）可以显著提高Cu-Zr二元系的玻璃形成能力.具有最大Tg/Ti值（0.626）的成分Cu60.3Zr37.2Nb2.5位于具有Cu8Zr5团簇和最深共晶点的Cu61.8Zr38.2向第三组元Nb的连线上.结合Cu-Zr二元体系的团簇结构讨论了Cu-Zr-Nb系块体非晶的形成.     

Al-Co-Y体系中富Al区非晶相的形成与结构演化

系统研究了铝基非晶态合金Al-Co-Y体系中富Al区的非晶形成能力.形成非晶结构最佳成分为AlssCosY7,条带临界厚度为230μm.此体系的玻璃形成能力对合金成分十分敏感.具有高的玻璃形成能力的合金未呈现出明显的玻璃转变特征.相对Trg和△Tx判据,"相选择"理论在寻找最佳合金成分和表征玻璃形成能力与成分的关系中更为有效.在非晶相的形成过程中,其主要竞争相为fcc-Al,Al3Y和Al9 Co2相.     

金属合金溶液热力学模型研究进展

对二元合金热力学数据的拟合和预测模型，由二元系数力学性质预测三元系热力学性质模型，以及多元溶液组元的活度相互作用参数表达式等金属合金溶液热力学模型的研究历史和目前进展进行了全面阐述，并对各模型的特征进行了评述。     

Ni-Cr-Fe-Mo-Co-W合金中宏观"黑斑"缺陷的特征分析

将晶界萃取碳复型技术同其它实验技术相验合,研究了Ｎｉ－Ｃｒ－Ｆｅ－Ｍｏ－Ｃｏ－Ｗ合金宏观“黑斑”缺陷特征的形成原因,认为“黑斑”缺陷主要是由晶界易腐蚀引起的。在“黑斑”区不均匀富集的钨、外元素主要以数量较多,尺寸较大的富含钼、钨的Ｍ６Ｃ形式存在于晶界上,使“黑斑”区的晶界易受腐蚀。该合金中的“黑斑”缺陷具有元素的宏观偏聚和微观偏聚相结合的特点。     

FORMATION OF QUASICRYSTALLINE PHASE IN RAPIDLY SOLIDIFIED Al-Fe-V-Si ALLOY

The icosahedral quasicrvstalline phase (i-phase)with the chemical composition of 82.4at%Al,8.8at?,3.6at%V and 5.2at%Si in melt spun Al-Fe-V-Si ribbons was found.It is suggested that the temperature and holding time of the melt prior to quenching are the important factors in the formation of the i-phase.     

THE ROLE OF NIOBIUM IN NICKEL-BASED SUPERALLOYS AND CHARACTERIZATION OF PM ALLOY EP741NP

1. IntroductionN iobium 'sprim ary role in superalloysisasa strengthenervia precipitation hardening and via solidsolution strengthening in a lesserextent. N iobium form s M C-type carbides in addition to the gam m adouble prim e (γ')phase N i3N b in iro…     

Morphological Characteristic and Formation Mechanism of Joint of Meltspun Cu—Sn Alloy Foils By Capacitor Discharge Welding

应用自制的微型电容储能电阻焊帆研究了快速凝固Cu-20％Sn包晶合金的储能焊连接行为及接头组织特征．微型接头由熔核区、半熔化区及热影响区组成，熔核为以细密β‘～Cu5．6Sn等轴晶为主相的快速凝固组织，熔合区宽度仅2．0—3．0μm，热影响区组织未发生明显变化，储能焊接头组织与快速凝固箔材一致性好．在电极压力及电磁力的共同作用下，过冷熔核中发生了一定程度的液相流动，形成以加压电极为对称轴向四周辐射，并以结合面为对称面，向侧面延伸的弯曲流线．气孔是快速凝固Cu—Sn合金储能焊接头主要的焊接缺陷．随电极压力的增大，气泡半径急剧减小，当电极压力大于1．0MPa时，该减小趋势趋于缓和．液相流动促进气泡的碰撞、合并及迁移是气孔沿熔核周边分布的主要原因．     

实用M2052合金阻尼行为表征

名义组分为Mn-20Cu-5Ni-2Fe(原子分数，％)的M2052合金，具有很高的强度和阻尼性能．对该合金在不同条件下的阻尼性能采用多种方法进行了表征．该合金的高阻尼态出现在一个临界温度以下，该温度可以通过改变组分和热处理来调整．合金的室温阻尼性能强烈地依赖于频率、应变振幅以及静载荷的大小．     

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A EXTRUDED RAPIDLY SOLIDIFIED AIFeVSi ALLOY

ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＭＥＣＨＡＮＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＡＥＸＴＲＵＤＥＤＲＡＰＩＤＬＹＳＯＬＩＤＩＦＩＥＤＡＩＦｅＶＳｉＡＬＬＯＹ￥Ｚｅｎｇ，Ｙｕｘｉａｏ；Ｌｉ，Ｓｏｎｇｒｕｉ；Ｌｉ，Ｗｅｎｘｉａｎ；Ｗａｎｇ，Ｒｉｃｈｕ；Ｈｕ...     

MICROSTRUCTURAL FORMATION MECHANISM OF SEMI-SOLID AZ91D ALLOY

With the help of an electromagnetic stirring device and alloy melt quenching technology, the microstntcture of semi-solid AZqlD magnesium alloy slurry stirred by a rotationally electromagnetic fieM was studied and the experimental results are shown as the following. The primary α-Mg grains are refined obviously when the slurry is stirred by a rotational electromagnetic field during continuously cooling and they are eventually changed to fine rosette grains or spherical grains. If the above semi-solid slurty is further stirred isothermally for some time, much more spherical primary α-Mg grains can be obtained. If the melt is first cooled down to a given semi-solid temperature and then starts being stirred by the rotational electromagnetic field, the primary α-Mg dendrites will be large, and a longer time will be taken and a larger stirring power will be needed for the secondary army of the dendrites to be remelted on the roots to prepare an ideal semiolid slurry. Theoretical analysis indicates that the strong flow motion leads to a more even temperature field and a solute field and stronger man-made temperature fluctuation in the AZglD magnesium alloy melt so that the spherical primary α-Mg grains are increased in the slurry. Moreover, all the measures promoting the temperature fluctuation will be favorable to the formation of spherical primary α-Mg grains and all the factors increasing the arm＇s root remelting difficulty will be favorable to the formation of rosette-type primary α-Mg grains.     

QUANTITATIVE CHARACTERIZATION OF STRESS-STRAIN HYSTERESIS LOOPS OF Cu-Zn-Al SHAPE MEMORY ALLOY

1. IntroductionAs a smart material, shape memory alloys (SMAs) have found many applications dueto their special shape memory characteristics[1--5]. Typical such alloys are TiNt, TiNibased and Cu-based alloys. It is often importallt to know their st ress- st r al n- t e mp erat urerelations before suitable designs can be made for particular applicationsI6---'2]. However, thest ress- strain- t emperat ure relations of S M As are nonli near and have bys teresis [ 1 o -- 15]. Andthe shape of…