Al─Ti─C─B中间合金细化剂的研究

研究了新近开发的Ａｌ－Ｔｉ－Ｃ－Ｂ中间合金细化剂，检查了其显微组织及细化工业纯铝及含Ｚｒ铝合金的性能，并与Ａｌ－Ｔｉ－Ｂ中间合金细化剂进行了对比。结果表明：Ａｌ－Ｔｉ－Ｃ－Ｂ中间合金细化剂含有Ａｌ３Ｔｉ、ＴｉＢ２和ＴｉＣ三种第二相，它们形成尺寸细小弥散分布的多相粒子团，其细化工业纯铝晶粒的能力明显优于Ａｌ－Ｔｉ－Ｂ中间合金细化剂，并克服了Ａｌ－Ｔｉ－Ｂ中间合金细化剂易被Ｚｒ原子毒化的弱点。分析认为，Ａｌ－Ｔｉ－Ｃ－Ｂ中间合金优异的细化性能归功于多相粒子团表面凹陷处的物理化学作用     

定向凝固NiAl－Cr、NiAl－（Cr，Mo）共晶合金的显微结构研究

利用ＴＥＭ研究了两种定向凝固共晶合金ＮｉＡｌ－Ｃｒ和ＮｉＡｌ－（Ｃｒ，Ｍｏ）在不同状态下的显微结构特征，以能了解其复相强韧化作用。它们的显微结构分别呈棒状和层状形态。共晶两相间的界面呈半共格，存在不可动的位错网。此外，在（Ｃｒ，Ｍｏ）相上分布着细小的共格ＮｉＡｌ析出相。经形变后，ＮｉＡｌ相中的位错被界面位错网钉扎，（Ｃｒ，Ｍ０）相中未发现位错。经１３００Ｋ×５００ｈ热处理，共晶形态稳定不变，ＮｉＡｌ析出相稍显粗化。     

纳米晶Al88Ce2Ni10铝合金的形成

通过晶化法，可以将快凝Ａｌ８８Ｃｅ２Ｎｉ１０非晶铝合金制备成纳米晶合金。纳米晶合金的组织为αＡｌ固溶体和金属间化合物Ａｌ３Ｎｉ及Ａｌ１１Ｃｅ３组成的多相纳米晶结构。在６０３～７７３Ｋ较宽退火温区内，用Ｓｃｈｅｒｅｒ公式计算各晶化相，得到αＡｌ、Ａｌ３Ｎｉ及Ａｌ１１Ｃｅ３的晶粒尺寸分别为３１～３１６、２２～２０７及１９～１６５ｎｍ。结果表明，通过控制热处理条件，可以获得不同晶粒尺寸的纳米晶合金。其中获得晶粒细小、结构均匀超细纳米晶合金的最佳退火温度为第二ＤＳＣ峰值温度附近     

Al—Ti—C—B中间合金细化剂的研究

研究了新近开发的Ａｌ－Ｔｉ－Ｃ－Ｂ中间合金细化剂，检查了其显微组织及细化工业纯铝及含Ｚｒ铝合金的性能，并与Ａｌ－Ｔｉ－Ｂ中间合金细化剂进行了对比。结果表明，Ａｌ－Ｔｉ－Ｃ－Ｂ中间合金细化剂含有Ａｌ３Ｔｉ、ＴｉＢ２和ＴｉＣ三种第二相，经小弥散分布的多相粒子团，其细化工业纯铝晶粒的能力明显优于Ａｌ－Ｔｉ－Ｂ中间合金细化剂，并克服了Ａｌ－Ｔｉ－Ｂ中间合金细化易被Ｚｒ原子毒化的弱点，分析认为Ａｌ－Ｔｉ－Ｂ     

Al-Mg-Li-Zr合金超塑性能的研究

对ＡｌＭｇＬｉＺｒ（０１４２０）合金的超塑性进行了研究，发现该合金经适当形变热处理后，可以获得良好的超塑性能。显微组织观察表明，经适当形变热处理后的０１４２０合金，由于基体内弥散分布大量第二相粒子，在超塑变形时能获得稳定、等轴的细晶结构，因而超塑效应十分显著。     

Ni7Hf2／Ni3Al共晶的微观组织特征

针对ＮｉＡｌＨｆ三元系，寻找出形成Ｎｉ７Ｈｆ２／Ｎｉ３Ａｌ共晶成分的合金，结合光学金相、透射电镜、Ｘ射线衍射、电子探针等技术，研究了这种合金的相结构、形态和组成，分析了γ′／Ｎｉ７Ｈｆ２共晶的界面热稳定性，并提出了降低Ａｌ含量，从而消除枝晶间有害相βＮｉＡｌ／Ｎｉ７Ｈｆ２共晶的方法     

双相层片型TiAl基合金中γ相的形变孪生

应用ＴＥＭ分析研究了Ｔｉ－４８Ａｌ双相合金在不同温度经不同压缩量变形后的微观组织结构。试验结果及理论分析表明，层片型组织中γ相的形变享生具有选择性，形变孪晶与γ基体层片界面的交线属〈０１」类型；交线为〈１１０」类型的形变孪晶，不论室温，高温，压缩变形时都难以形成。     

定向凝固NiAl—28Cr—5.5Mo-0.5Hf合金中Ni_2AlHf相和Ni_(16)Hf_6Si_7相的研究

少量的Ｈｆ（０．５％）加入到定向凝固的ＮｉＡｌ－Ｃｒ（Ｍｏ）合金中,会产生Ｈｅｕｓｌｅｒ相Ｎｉ２ＡｌＨｆ,该相呈网状分布在ＮｉＡｌ／Ｃｒ（Ｍｏ）相界面区域．Ｎｉ２ＡｌＨｆ与ＮｉＡｌ之间不存在固定的晶体学取向关系,但有时也发现二者存在立方－立方取向关系：［１１１］ＮｉＡｌ［１１１］Ｈ,（１０１）ＮｉＡｌ／／（２０２）Ｈ,并通过高分辨电子显微照片分析了二者界面的精细结构由于定向凝固过程中,Ｓｉ元素进入到合金中,所以在此合金中发现了Ｇ－相Ｎｉ１６Ｈｆ６Ｓｉ７．细小弥散的Ｎｉ１６Ｈｆ６Ｓｉ７相呈立方体形状,与Ｎｉ２ＡｌＨｆ相相伴分布在ＮｉＡｌ／Ｃｒ（Ｍｏ）相界面附近同时讨论ＴＮｉＡｌ／Ｎｉ２ＡｌＨｆ及ＮｉＡｌ／Ｎｉ１６Ｈｆ６Ｓｉ７的界面能量,Ｎｉ１６Ｈｆ６Ｓｉ７相在ＮｉＡｌ中析出的惯习面和Ｎｉ２ＡｌＨｆ相及Ｎｉ１６Ｈｆ６Ｓｉ７相分布形态的成因     

TiAl合金PST晶体断裂过程原位TEM观察

利用ＴＥＭ原位应变观察技术研究了ＴｉＡｌ合金ＰＳＴ晶体中裂纹扩展过程。发现界面与裂纹的交互作用与界面类型有关，不对称的伪孪晶界面（γ／γＰ）对裂纹扩展的阻碍最强烈。片层界面以及二次裂纹导致的裂纹分叉是层状组织韧化ＴｉＡｌ合金的重要原因。当裂纹与片层界面的夹角不同时，γ相所表现的两种截然不同的断裂方式表明在ＴｉＡｌ合金的脆性本质中包含有位错动力学的因素。     

Y2O3涂层对Ti纤维与Ti／TiAl复合材料性能影响的研究

介绍了涂覆Ｙ２Ｏ３的Ｔｉ纤维增强γ－ＴｉＡｌ基复合材料的研究结果，分析了其界面结构和力学性能特征。试验结果表明，用物理气相沉积法（ＰＶＤ）在其表面涂覆Ｙ２Ｏ３层的Ｔｉ纤维增强ＴｉＡｌ基复合材料，不仅使ＴｉＡｌ合金的弯曲强度提高２５％，而且在同一工艺条件下使Ｔｉ纤维与ＴｉＡｌ基体间的界面反应层厚度由原来的３０μｍ减小到１４μｍ，界面有新相Ｔｉ３Ａｌ产生。     

Plasticity in multiphase intermetallics

We have studied the mechanical behavior of model NiAl-based eutectic composites to gain insight on micromechanisms of plasticity in multiphase intermetallics. We show that in composites where the NiAl matrix and the reinforcing ductile second phase can deform compatibly due to easy slip transfer across interfaces, high room temperature tensile ductility and fracture toughness are obtained. In composites where interfaces are strong barriers to slip transfer and the metallic second phase has high strength and limited ductility, incompatible deformation of the two phases results in negligible tensile ductility and limited toughness enhancement. Factors that affect ease of slip transfer across interfaces are discussed. Calculations of dislocation pile-up stresses are used to predict whether slip is activated prior to cleavage or vice-versa for a given set of respective yield strengths and crystallographic orientation relationships between the two phases.     

基于过冷奥氏体动态相变的热轧TRIP钢组织控制 Ⅱ.动态相变后冷却速率

通过热模拟压缩实验,研究了铁素体相变前的奥氏体晶粒尺寸对基于动态相变的热轧C-Mn-Al-Si系TRIP钢组织及力学性能的影响。结果表明,减小原始奥氏体晶粒尺寸,可促进动态相变时的铁素体相变动力学,有利于铁素体、贝氏体及残余奥氏体等相分布更为均匀,获得的贝氏体束及贝氏铁素体尺寸较小,残余奥氏体的体积分数及C含量均较高,细小的颗粒状残余奥氏体数量较多且弥散分布,因此可获得具有较高强度和优良塑性的热轧TRIP钢。     

CREEP DEFORMATION OF INTERMETALLIC ALLOYS

ＣＲＥＥＰＤＥＦＯＲＭＡＴＩＯＮＯＦＩＮＴＥＲＭＥＴＡＬＬＩＣＡＬＬＯＹＳＧｅｒｈａｒｄＳａｕｔｈｏｆｆ（Ｍａｘ－Ｐｌａｎｃｋ－ＩｎｓｔｉｔｕｔｆｕｒＥｉｓｅｎｆｏｒｓｃｈｕｎｇＧｍｂＨ．，Ｄ－４００７４Ｄｕｓｓｅｌｄｏｒｆ，Ｇｅｒｍａｎｙ）Ａｂｓｔ...     

Ti-4.5Al-5Mo-1.5Cr合金增韧的价电子理论研究

利用余氏固体与分子经验电子理论和程氏改进的TFD理论计算了Ti-4.5Al-5Mo-1.5Cr与Ti-6Al-4V两种合金的相空间及其异相界面价电子结构。利用价电子结构参数－相结构因子和界面结合因子，分析讨论了合金元素Mo,Cr和V对Ti-4.5Al-5Mo-1.5Cr与Ti-6Al-4V钛合金相空间及其异相界面价电子结构的影响，进而在电子结构层次上揭示了Ti-4.5Al-5Mo-1.5Cr合金增韧的微观本质原因。     

Multiscale mechanics of TRIP-assisted multiphase steels: I. Characterization and mechanical testing

The mechanical behaviour of transformation-induced plasticity (TRIP)-assisted multiphase steels is addressed based on three different microstructures generated from the same steel grade. The mechanisms responsible for the work-hardening capacity and the resulting balance between strength and resistance to plastic localization are investigated at different length scales. The macroscopic mechanical response is determined by simple shear, uniaxial tension, Marciniak and equibiaxial tension supplemented by earlier tensile tests on notched and cracked specimens. It is shown that the transformation rate reaches a maximum for stress states intermediate between uniaxial tension and equibiaxial tension. At an intermediate length scale, the true in situ flow properties of the individual ferrite–bainite and retained austenite phases are determined by combining neutron diffraction and digital image correlation. This combined analysis elucidates the partitioning of stress and strain between the different constitutive phases. Based on these results, supplemented by transmission electron microscopy and electron backscattered diffraction observations, a general overview of the hardening behaviour of TRIP-assisted multiphase steels is depicted.     

A physico-chemical approach in binary solid-state interdiffusion

A physico-chemical approach is developed, which can be used in binary diffusion couples to determine diffusion parameters of product phases with a wide homogeneity range, as well as phases with a narrow homogeneity range. It is demonstrated that this approach is basically equivalent to the diffusion-based treatment. However, the physico-chemical approach pedagogically sheds light on the chemical reactions occurring during interdiffusion at the interphase interfaces. This theory can be used in any binary system for any end-member condition to explain single-phase or multiphase diffusion-controlled growth. Ni–Al and Ag–Zn systems are considered here to calculate diffusion parameters following the physico-chemical approach. It is evident from our theoretical analysis and experimental evidence that in the case of presence of a stable Kirkendall marker plane one should expect the presence of duplex grain morphology in a particular phase layer.     

Cu-71.8%Ag共晶体中两相的台阶界面及晶体取向

采用熔铸法制备了Cu-71.8%Ag(质量分数)合金,研究了共晶体中两相的位向关系和界面结构.约50%的相界面两侧Cu和Ag两相位向对称于(111)晶面.出现对称位向的相界面形态为台阶状,台阶平面与(111)平行,高度为(111)Cu和(111)Ag晶面间距的平均值,宽度为3-4个(11-1)Cu晶面间距.在此界面上,每隔3-4个(11-1)Cu晶面间距出现一个点阵重合位置.     

O点阵模型及其在界面位错计算中的应用

介绍了描述O点阵特征的基本参量：主O点陈基矢，主O点阵面和O胞壁的定义和计算公式，提供了一般界面上周期位错结构的矩阵方法和计算特殊界面位错结构的简易矢量方法：还分析了O点阵描述界面位错的条件和局限，讨论了一般界面和大错配界面上位错结构的计算。     

低碳微合金钢中针状铁素体的形成与控制

低碳微合金钢连续冷却时都会产生多种类型的中温转变组织,低冷速下主要得到粒状贝氏体组织,高冷速下主要得到板条贝氏体组织．连续冷却时,在较高中温转变温度范围可形成针状铁素体,其转变受冷却速度和过冷温度影响．通过控冷可以在低碳微合金钢中得到贝氏体和针状铁素体多相组织,利用针状铁素体能改善高强度低碳微合金钢的综合力学性能．     

Microstructure and mechanical properties of metallic glass/metallic glass composites

We report microstructure and mechanical properties of bulk metallic glass (BMG)/metallic glass composites fabricated by mechanical alloying with subsequent consolidation process. The microstructural investigations of a bulk composite reveal that a submicron-scale layered structure with irregular interfaces consists of three amorphous phases in tornado-like morphology. Based on these results, poor plasticity of the metallic glass composite can be understood possibly due to the irregular interfacial morphology of the submicron-scale heterogeneous amorphous phases throughout the materials.