铸铁基体及石墨形状超声波无损伤检验探讨

利用超声波（速度和强度）来测试铸铁中不同的石墨形状参数、基体结构及与此相关的机械性能。结果表明，石墨形状参数和超声波速度有着明显的对应关系，但是基体与超声波之间的影响则不明显。随着石墨形状参数的增加，超声波的幅值也随之变化，发现铁素体、珠光体、正火马氏体和贝氏体有相同的特性，但是基体中较大数量的正火马氏体或珠光体都会导致超声波幅值的增大。     

铌对冷硬铸铁组织和性能的影响

研究了铌对冷硬铸铁组织及力学性能的影响，结果表明，微量铌可能改善冷硬铸铁的铸态组织，提高其力学性能，但铌加入量过高会得到相反的效果，铌的加入量以０．０５％左右为宜。     

BGA焊点界面化合物纳米压痕力学行为

利用纳米压痕法对BGA焊点(Cu,Ni)₆Sn₅,Cu₆Sn₅,Cu₃Sn界面化合物(IMC)进行了压痕试验.基于Oliver-Pharr法确定了(Cu,Ni)₆Sn₅,Cu₆Sn₅,Cu₃Sn的弹性模量和压痕硬度,研究了加载速率对IMC纳米压痕力学行为的影响及其变化规律.结果表明,锯齿流变效应与加载速率的大小是相关的.在加载速率较小的情况下(Cu,Ni)₆Sn₅,Cu₆Sn₅,Cu₃Sn都具有锯齿流变效应,但程度不同;在加载速率较大的情况下(Cu,Ni)₆Sn₅,Cu₃Sn锯齿流变效应不明显,而Cu₆Sn₅的锯齿流变效应相对明显.(Cu,Ni)₆Sn₅,Cu₆Sn₅,Cu₃Sn界面IMC的弹性模量分别为126,118,135 GPa;压痕硬度分别为6.5,6.3,5.8 GPa;含镍的(Cu,Ni)₆Sn₅化合物弹性模量和压痕硬度均比Cu₆Sn₅的值要高.     

D型石墨奥氏体基体铸铁抗氧化性能的研究

对D型石墨奥氏体基体铸铁的化学成分进行了试验设计,研究了高温不同温度下它的抗氧化性能,探讨了抗氧化机理.结果表明,D型石墨奥氏体基体铸铁具有较好的抗氧化性能,可为该合金用于玻璃模具提供生产依据.     

石墨形态和基体组织对铸铁断裂过程的影响

研究了石墨片混乱度Ｓ＝０的Ｆｅ－Ｃ合金和球墨铸铁在不同受力状态下的裂纹扩展现象，以及基体组织对断裂形貌的影响，试验发现：当裂纹遇到与其平行的片状石墨时，裂纹将在石墨内部以（０００１）面之间的解理而扩展；当裂纹遇到与其垂直的片状石墨时，裂纹将沿石墨／基体界面处扩展，也即界面的脱粘；当裂纹遇到球状石墨时，裂纹主要的二次石墨中前进，裂纹在铁素体－下贝氏体中以在铁素体中的扩展为主。     

高镍铬离心复合铸铁轧辊界面波的研究

分析了高镍铬离心复合铸铁轧辊界面波偏高的问题,提出了造成界面波偏高的基本原理;针对不同原理提出了相应的解决措施.     

铸铁和镀锌铸铁在深井水中腐蚀行为

恒电位极化曲线表明铸铁和镀锌铸铁在给定的深井水中均发生氧去极化腐蚀，前者受氧扩散过程控制较为显著，后者受阴极过程沉积物的影响，并用线性极化法和失重法测定腐蚀率，表明在铸铁表面镀锌作为深井水泵的腐蚀控制措施是有效的。     

高铬铸铁和中碳钢复合界面结合情况分析

通过液固结合的方式制备高铬铸铁和中碳钢双金属复合材料。对高铬铸铁和中碳钢采用不同的体积比进行实验,就得到的试样进行了界面结合组织的分析和讨论,揭示了金属复合的原理。同时通过界面显微硬度的测试,说明了采用复合工艺可以达到发挥两种材料共同性能的目的。     

基体组织对高铬铸铁磨损行为影响的研究

研究了具有规定碳化物体积份数而基体组织不同的高铬铸铁在两体静磨损条件下的磨损特性。结果表明:随着磨料的改变,合金抗磨能力发生变化,磨料硬度高,磨损量大。     

铸铁凸轮轴白口区中的石墨异常析出

介绍了天津夏利汽油机凸轮轴的生产条件和技术要求，分析了其激泠部位的石墨异常析出（黑线）现象，并进行了辚线的耐磨性试验，试验结果：黑线处磨损体积为白口区的1．5～3倍，认为黑线缺陷会造成凸轮轴的早期磨损报废。根据生产实践经验，给出了防止和消除黑线缺陷的有效方法。     

MECHANICAL BEHAVIOUR OF GRAPHITE AND ITS ADJACENT ZONE TO MATRIX INTERFACE IN CAST IRON

The micro-processes on tensile deformation and fracture of graphite-matrix interface incast iron with ferrite matrix under SEM have been observed in situ.It was revealed thatthe graphite in cast iron would not be regarded as a cavity and not formed yet notchstress concentration.A new explanation on the effect of graphite on strength of cast ironwas suggested.     

GROWTH MODE AND MODIFICATION OF GRAPHITE IN CAST IRON MELT

Using liquid quenching technique,the change of growth mode of graphite in cast iron meltwas analysed.Based on the interface structure theory of crystal growth,the concept ofmultiplication of spiral growth steps was advanced and two basic multiplication modelswere given.It was proposed that multiplication of spiral steps is responsible for the changeof growth mode of graphite in cast iron melt.The modifying elements such as Ce promotemultiplication of spiral steps,which is regarded as the core of modification.Originationof screw dislocation and branch of the sector blocks in radius direction,both of whichare essential to spheroidization of graphite in the melt,are caused by multiplication ofspiral steps:and so is thickening of graphite plates.     

稀土球铁中Ce的分布及作用

用定向凝固和电解萃取—放射性同位素测量技术,分析了球化剂Ce在球铁各相中的分布;配合测量石墨球化率,确定了球铁含Ce量与石墨球化程度的关系,结果表明:Ce在球铁中主要以合金化Ce的形式存在,但石墨相Ce含量是石墨球化程度的表征值;只有当石墨相Ce含量高于一定值时,石墨才能完全球化。     

STRUCTURAL CHANGE IN HEAT AFFECTED ZONE AND ITS INFLUENCE ON PROPERTIES OF WELDED WHITE CAST IRON

The structural change in heat affected zone(HAZ)and its influence on properties of welded white cast iron have been investigated by means of thermal cycle simulation technique.The structure of the white cast iron at peak temperature 800℃ was examined as cementite in pearlitic matrix,of which the hardness and impact toughness are the lowest,while the struc- ture after cyclic heating at high peak temperature is mainly cementite together with twin martensite,of which the hardness and impact toughness are rather higher.The phase bounda- ries in the structure of low hardness are smooth and regular as well as with fine precipitates. Both the cleavage and interphase fracture were revealed in the structure of low hardness,while the transgranular fracture was found in those areas of higher hardness.     

EFFECT OF NITROGEN ON GRAPHITE MORPHOLOGY IN GRAY CAST IRON

The distribution of N and morphology of graphite in gray cast iron containing N werestudicd by adopting the man-made specimens of Fe-C-Si-Mn alloys with some N added.The N adsorbed along the interfaces between graphite and matrix together with solid-solutioned in graphite is believed to be the principal cause of morpholongical variationof graphite.     

氮对灰铸铁中石墨组织的作用

本文研究了氮在灰铸铁中的分布及含氮灰铸铁石墨组织结构,结果表明,氮在石墨与基体界面上的吸附和在石墨中的固溶是氮使石墨组织形态发生变化的主要原因。     

SIZE DISTRIBUTION AND BEHAVIOUR OF VC PARTICLES IN FERRITIC NODULAR CAST IRON

Size distribution and precipitation of VC particles in ferritic nodular cast iron havebeen examined by techniques of ultrasonic screening,small angle X-ray scattering andchemical dissolution.The VC particles are sized over a wide range.The superfine ones,dispersed in the ferritic matrix,are the majority.A saturated dispersion with ultrafineVC particles may be approached as the V content increasing in the iron.Thi5 seems toplay an important role in the precipitation strengthening for ferritic nodular cast iron.     

铁素体球铁中VC的粒度分布和作用

采用超声波筛分、X射线小角散射及化学溶解等方法,分析了铁素体球铁中VC的粒度分布和析出规律。结果表明:VC的粒子直径有很宽的分布范围,但超细VC占粒子总数的绝大部分;超细VC弥散分布于铁素体基体,随球铁含钒量增加,超细VC量趋于饱和,这部分碳化物在球铁的强化中起主要作用。     

白口铸铁焊接热影响区组织转变及其对性能的影响SCIEI

采用热模拟技术再现白口铸铁焊接热影响区的组织,研究了焊接热影响区的组织转变及其对性能的影响,发现热循环峰温为800℃时,白口铸铁的组织为渗碳体加珠光体,其硬度最低,冲击韧性最差;高峰温热循环作用后的组织主要为渗碳体加孪晶马氏体,其硬度较高,冲击韧性较好;低硬度组织的相界面平滑、圆整,并且界面上有细小化合物析出,其断裂为解理加沿相界断裂,高硬度组织的断裂为穿晶断裂。     

铸铁孕育处理时的石墨核心研究

将铁水用75FeSi孕育后液淬,终止其溶解过程,在溶解区中出现已经生长石墨相的非金属夹杂物,它们随后又溶回铁水中去.但已经复盖有石墨相的晶核能存在较长的时间孕育剂的作用是提供一个碳的过冷溶液,使位于其中的非金属夹杂物活化成为晶核