A FORMULA FOR γ′-PHASE AMOUNTING IN PRECIPITATION HARDENING NICKEL-BASE SUPERALLOYS

<正> 一、引言 近年来,由于合金设计和合金相分离,需要计算合金中γ＇相的数量。Woodyatt,Sims等利用对合金各相逐次递减的方法,得到合金中γ＇相的数量。Decker应用回归分析方法,由某些工业合金的实验资料,得出一个以体积百分数表达的计算公式. 作者对目前已经发表的沉淀强化镍基合金γ＇相的大量实验资料,进行综合分析,归纳成以下三条: 1.合金中所含碳化物相数量较少(总量在3％以下),其它相(如硼化物等)含量甚微,二者总和比γ＇相的数量少得多,可予以忽略不计,因而这种合金可以视为由γ奥     

THERMODYNAMIC STUDY OF BAINITIC TRANSFORMATION IN Fe-C ALLOYS

The growth of bainitic ferrite is a couple process of the shear transformation of Fe atoms withthe diffusion of C atoms.The diffusion growth of the ferrite is impossible when the tempera-ture is below 400℃,and the paraequilibrium shear growth may occur at the temperature be-low 550℃.This paraequilibrium shear growth model explains the overlap of the bainitescreated from two growth mechanisms at 400—550℃.     

HIGH TEMPERATURE CORROSION OF PREOXIDIZED Ni-Al ALLOY IN CHLORINE

ＨＩＧＨＴＥＭＰＥＲＡＴＵＲＥＣＯＲＲＯＳＩＯＮＯＦＰＲＥＯＸＩＤＩＺＥＤＮｉ－ＡｌＡＬＬＯＹＩＮＣＨＬＯＲＩＮＥＨＩＧＨＴＥＭＰＥＲＡＴＵＲＥＣＯＲＲＯＳＩＯＮＯＦＰＲＥＯＸＩＤＩＺＥＤＮｉ－ＡｌＡＬＬＯＹＩＮＣＨＬＯＲＩＮＥ￥Ｔｕ，Ｊｉａｎｇｐｉ...     

TEMPERATURE DEPENDENCE OF ANTIFERRO-MAGNETIC γ-Fe-Mn-Al AND γ-Fe-Mn-Cr ALLOYS UPON RESISTIVITY

测定了面心立方结构Fe-Mn-Al,Fe-Mn-Cr合金的电阻率及磁化率与温度的关系,这些合金均呈现顺磁性-反铁磁性转变,并伴有电阻率-温度关系的反常变化.电阻率测定的结果说明,在Néel温度T_N以下,由于反铁磁有序散射,使电阻率反常增大,dρ/dT减小或变为负值,ρ-T曲线向上弯曲,反常电阻率随T_N的下降和X-T曲线峰值的升高而增大.Al的加入量对反铁磁转变引起的电阻率变化有强烈的影响,随Al浓度的增加,反常电阻率急剧增大,这可能与Al使合金中Fe离子位置存在较大局域净磁矩有关.Cr对反铁磁电阻率的影响远较Al小.本文的实验结果揭示,基于顺磁性-反铁磁性转变,研制一种温度系数较小的Fe-Mn-Al-Cr系新电阻合金是可能的。     

INFLUENCES OF ASSOCIATED AND SEPARATE PRECIPITATION OFγ′WITH γ" ON THERMAL STRUCTURE STABILITY IN INCONEL718 TYPE ALLOYS

用透射电镜观察了Inconel718及其改型合金中的时效析出组织调整Nb,Ti,Al的含量及比例,可以得到与通常合金中γ′和γ″单独析出有所不同的γ′和γ″的复合组织及包覆组织两类析出形态、其中γ″在γ′上析出的包覆组织具有较好的高温长期时效组织稳定性过时效试验结果表明.改型合金不同于Inconel718合金γ″致δ的相转变,却以强化相溶解而使材料软化     

A DIRECTIONAL COARSENING MECHANISM OF THE γ＇-PHASE DURING CREEP OF A SINGLE CRYSTAL NICKEL-BASE SUPERALLOY

对[001]取向单晶镍基合金恒载拉伸蠕变不同阶段的组织形貌进行了SEM,TEM观察和EDAX成分分析,研究了γ＇相定向粗化过程及机理结果表明：蠕变初期,两相邻γ＇相呈侧平面对接方式,沿垂直于应力轴方向定向生长为类似筛网的核状组织,外加应力使γ＇／γ界面共格应变减少,应变能降低,释放的能量是促使合金元素定向扩散形成筏状γ＇结构的驱动力．     

GROWTH MORPHOLOGY OF γ'-DENDRITE DURING HIGH TEMPERATURE AGEING OF Ni-BASE SUPERALLOY

在Ｒｅｎｅ＇Ｎ４单晶镍基高温合金的高温时效过程中，发现γ＇粒子由立方形逐渐形成梅花状、并继续演变成枝晶形态，同时γ＇枝晶具有择域生长特性．公式推导证明，γ＇粒子的生长尺寸有一临界值α＇超过这一临界值后，γ＇粒子将通过错配位错造成粒子周边凹陷，以协调γ＇能量的增加，并进一步发展为枝晶状．     

DIRECTIONAL COARSENING OF THE γ'-PHASE DURING COMPRESSION CREEP OF A SINGLE CRVSTAL NICKEL-BASE SUPERALLOY

对「００１」取向单晶镍基合金恒温恒载压缩蠕变不同时间的组织形貌进行了ＳＥＭ和ＴＥＭ观察表明：蠕变初期,两立方γ‘相沿平行于应力轴方向扩散相连定向生长成为条形筏结构;垂直通道中基体「００１」晶向共格应变量减小,应变能降低是合金元素定向扩散形成γ’相符结构的驱动力;压缩与拉伸蠕变相比较,γ’相形筏所需要的时间较长,应力较大。     

INFLUENCE OF DISPERSED γ′ ECIPITATEDPARTICLES ON MARTENSITE MORPHOLOGY IN Fe-Ni Co-Ti ALLOYS

Fe-Ni-Co-Ti合金中弥散析出的γ′粒子,当直径在20—50nm时,低温下生成的马氏体具有薄片状马氏体特征;由于γ′粒子的钉扎作用,马氏体界面不光滑.当γ′粒子直径小于5nm时,低温下生成具有良好热弹性的薄片状马氏体;当γ′粒子直径大于5nm,出现断续状马氏体,而且随γ′粒子的长大,断续状马氏体变大,数量增多.当γ′粒子直径为10—15nm时,低温下生成透镜状或蝶状马氏体。     

A PAT STUDY OF INFLUENCES OF PRECIPITATION ON DEFECTS AND ELECTRONIC DENSITY IN Al-Li-Cu-Mg-Zr ALLOYS

ＡＰＡＴＳＴＵＤＹＯＦＩＮＦＬＵＥＮＣＥＳＯＦＰＲＥＣＩＰＩＴＡＴＩＯＮＯＮＤＥＦＥＣＴＳＡＮＤＥＬＥＣＴＲＯＮＩＣＤＥＮＳＩＴＹＩＮＡｌＬｉＣｕＭｇＺｒＡＬＬＯＹＳ①ＷｕＷｅｉｍｉｎｇ，ＧａｏＹｉｎｇｊｕｎ，ＬｕｏＬｉｘｉｏｎｇ，ＤｅｎｇＷ...     

HIGH TEMPERATURE OXIDATION AND STRUCTURE OF SCALE AND WHISKERS FOR Fe-Ni-Cr SEALING ALLOYS

The oxidation rate,the growth,morphology and structure of oxide scale and whiskers forFe-Ni-Cr sealing alloys in H_2-H_2O atmosphere at high temperatures have been studied.The growth rate of scale is controlled by diffusion.The scale is composed of Cr_2O_3 andspinel(Fe,Mn)O·Cr_2O_3 and the oxide whisker,are spinel(Fe,Mn)O·Cr_2O_3.     

MICROSTRUCTURE STUDY OF CONSTITUENT PHASES IN 2024 SERIES Al ALLOYS

X-ray microanalysis,convergent beam electron diffraction(CBD)and selected area electrondiffraction(SAD)studies on the structures and compositions of the constituent phases in2024 series Al alloys have been conducted.Partial substitution of alloying elements is found tooccur in all the constituent phases,which cause small deviations from the stoichiometric com-positions reported in these ternary compounds.The dominant phase is α-Al_(12)(FeMn)_3Si whichhas a body center cubic crystal structure with the Im■ space group and a=1.25 nm.The nextdominant phase is Cu_2FeAl_7 which has a primitive tetragonal crystal structure with theP4/mnc space group and a=0.6336 nm,c=1.487 nm.The minor phase is α'-Al_(12)Fe_3Si hav-ing α primitive cubic crystal structure with the Pm■ space group and α=1.27 nm.     

EFFECTS OF HIGH TEMPERATURE PRETREATMENTS ON HIGH TEMPERATURE FRACTURE BEHAVIOR OF SiC-C／SiC

The samples made from a SiC-C/SiC composite were pretreated in Ar under creep, fatigue, creep and fatigue interaction, as well as in dry oxygen and wet oxygen under fatigue at 1300℃ for 15 hours, The fracture behaviors of the pretreated samples were investigated at 1300℃. The loading-strain curves and the microstructures of the sample were compared with each other. The various of high temperature tensile behaviors was attributed to the different microstructures resulted from different high temperature pretreatments.     

A THERMODYNAMIC STUDY OF THE Fe-C SYSTEM——I. THERMODYNAMICS OF LIQUID Fe-C ALLOYS

作者在本文中综合分析了关於液态铁碳合金中碳活度测定的諸家研究结果並比较其优劣. 然后根据Richardson与Dennis用CO_2/CO平衡法的实验数据,用Darken与Smith的统计模型与最少假定,导出了液态鉄碳合金中α′_c与N′_c的关系(α′_c=logγ′_c,/(N_Fe′)~2,标准状态为石墨),并温度对此关系的影响.计算结果符合於(i)鉄液内石墨溶解度的实验数据;(ii)与用电动势法测定液态铁碳合金中碳活度的实验数据;及(iii)奥氏体、铁液、石墨共晶平衡的要求. 根据本文所导出的α′_c-N′_c曲綫,作者算得石墨在鉄液内的溶解热为3930卡;然后依此及其他必需数据,导出下列关系:C(石墨)=C[%],△F°=3930-9.21T. 最后作者从液态铁碳合金结构的观点讨论了图1中α′_c-N′_c曲綫的形状.     

INFLUENCE OF ASSOCIATED AND SEPARATE PRECIPITATION OF γ″ AND γ′ ON STRUCTURE STABILITY IN INCONEL718 AND MODIFIED ALLOYS

The precipitation behavior in Inconel 718 and modified alloys has been studied by means ofTEM.The structure of associated precipitation and compact morphology of γ″+γ′ were ob-tained by modifying the contents of Al,Ti and Nb.Experimental results show that the com-pact morphology of γ″+γ′ has the best structure stability at higher temperatures.Instead ofthe transformation γ″→δ in alloy 718 the dissolution of strengthening phases in modified alloyleads material degradation.     

MATHEMATICAL SIMULATION OF INTERACTIVE PHYSICAL PROCESSES IN HIGH TEMPERATURE ELECTROCHEMICAL DEVICES

A mathematical analogue of interactive mass transfer in some electrochemical processes hasbeen considered.A programme has been developed which calculates thermal and electrical phe-nomena in high temperature electrochemical devices,with the influence of magnetic fields beingtaken into consideration.     

INTERACTION BETWEEN CREEP AND FATIGUE OF A NICKELBASED SUPERALLOY IN738LC AT ELEVATED TEMPERATURE—DECREASING OF CYCLIC LIFE WITH INCREASING CREEP DEFORMATION

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｉｎｔｅｒａｃｔｉｏｎｂｅｔｗｅｅｎｃｒｅｅｐａｎｄｆａｔｉｇｕｅｃａｎｂｅｏｃｃｕｒｅｄｉｆｔｈｅｍａｔｅｒｉａｌｉｓｕｎｄｅｒｃｒｅｅｐｆａｔｉｇｕｅｌｏａｄｉｎｇ．Ｔｈｅｃｒｅｅｐｄｅｆｏｒｍａｔｉｏｎｕｓｕ...     

STUDY ON THE SHOCK WAVE CRYSTALLIZATION OF AMORPHOUS ALLOYS BY DSC

Shock wave and annealing crystallization of amorphous alloys FeSiB, FeMoSiB and FeCuNbSiB were studied by isothermal and non-isothermal DSC technique. It was found that the shock wave crystallization is very perfect, the fraction crystallized is very close to 100%, though the period of crystallization is very short, only about 10-4-10-6s. Their produced phases differ from the parent phase in structure and composition. The high velocity of the transformation is very difficult to explain by the diffusion theory of solid state phase transition.     

THE BEHMAVIORS OF (1/2)〈110] DISLOCATIONS IN γ-TiAl SINGLE CRYSTALS

[021]取向的γ—TiAl单晶（Ti—56％Al,原子分数）在－196－1000℃温度范围内压缩变形时主要形变方式为｛111｝（110］普通位错的滑移低温时,（1／2）（110］普通位错大多沿螺型及60°交角两种方向排列,井倾向于成组出现;而在反常屈服温度区域内,（1／2）（110］普通位错大多平行于其螺型方向,且形成许多位错拐点,其数目随温度的升高而增加;在反常屈服峰温以上,普通位错不具有特殊的方向性,且倾向于通过攀移向其它滑移面运动