CRYSTAL STRUCTURE OF A LONG－PERIOD ORDERED PHASE IN Fe－C MARTENSITE AND COMPUTER SIMULATION OF ITS ELECTRON DIFFRACTION PATTERNS

ＣＲＹＳＴＡＬＳＴＲＵＣＴＵＲＥＯＦＡＬＯＮＧ－ＰＥＲＩＯＤＯＲＤＥＲＥＤＰＨＡＳＥＩＮＦｅ－ＣＭＡＲＴＥＮＳＩＴＥＡＮＤＣＯＭＰＵＴＥＲＳＩＭＵＬＡＴＩＯＮＯＦＩＴＳＥＬＥＣＴＲＯＮＤＩＦＦＲＡＣＴＩＯＮＰＡＴＴＥＲＮＳＲＥＮＸｉａｏｂｉｎｇ；ＷＡ...     

CHARACTERS OF SEDIMENTATION OF SUSPENSION FLOCCULATED OR COAGULATED

ＣＨＡＲＡＣＴＥＲＳＯＦＳＥＤＩＭＥＮＴＡＴＩＯＮＯＦＳＵＳＰＥＮＳＩＯＮＦＬＯＣＣＵＬＡＴＥＤＯＲＣＯＡＧＵＬＡＴＥＤ￥ＫａｎｇＹｏｎｇ；ＨｕＸｉａｏｍｉｎ；ＤｅｎｇＣｈａｎｇｌｉｅ；ＬｕｏＱｉａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭｉｎｅｒａｌＥｎｇｉｎ...     

PROGRESS IN STUDIES OF ELECTROCATALYSTS AND DOPED CARBON ANODES IN ALUMINIUM ELECTROLYSIS CELLS

ＰＲＯＧＲＥＳＳＩＮＳＴＵＤＩＥＳＯＦＥＬＥＣＴＲＯＣＡＴＡＬＹＳＴＳＡＮＤＤＯＰＥＤＣＡＲＢＯＮＡＮＯＤＥＳＩＮＡＬＵＭＩＮＩＵＭＥＬＥＣＴＲＯＬＹＳＩＳＣＥＬＬＳＰＲＯＧＲＥＳＳＩＮＳＴＵＤＩＥＳＯＦＥＬＥＣＴＲＯＣＡＴＡＬＹＳＴＳＡＮＤＤＯＰＥ...     

INTERACTION OF PARTICLES WITH A SOLIDIFIED INTERFACE DURING SOLIDIFICATION OF METAL MATRIX COMPOSITE REINFORCED WITH PARTICLES

ＩＮＴＥＲＡＣＴＩＯＮＯＦＰＡＲＴＩＣＬＥＳＷＩＴＨＡＳＯＬＩＤＩＦＩＥＤＩＮＴＥＲＦＡＣＥＤＵＲＩＮＧＳＯＬＩＤＩＦＩＣＡＴＩＯＮＯＦＭＥＴＡＬＭＡＴＲＩＸＣＯＭＰＯＳＩＴＥＲＥＩＮＦＯＲＣＥＤＷＩＴＨＰＡＲＴＩＣＬＥＳＣＨＵＳｈｕａｎｇｊｉｅ;Ｗ...     

THE ESTABLISHMENT OF CALCULATION FORMULA FOR CASTING－ROLLING FORCE OF VISCOUS FLUID AND THE INFLUENCE OF TECHNOLOGICAL FACTORS

ＴＨＥＥＳＴＡＢＬＩＳＨＭＥＮＴＯＦＣＡＬＣＵＬＡＴＩＯＮＦＯＲＭＵＬＡＦＯＲＣＡＳＴＩＮＧ－ＲＯＬＬＩＮＧＦＯＲＣＥＯＦＶＩＳＣＯＵＳＦＬＵＩＤＡＮＤＴＨＥＩＮＦＬＵＥＮＣＥＯＦＴＥＣＨＮＯＬＯＧＩＣＡＬＦＡＣＴＯＲＳ￥Ｓｕｎ，Ｂｉｎｙｕ；Ｚｈａｎ...     

STABILITY OF WHISKERS AND INTERFACIAL MICROSTRUCTURE IN ALUMINUM MATRIX COMPOSITES REINFORCED BY K_2O·8TiO_2 WHISKERS

ＳＴＡＢＩＬＩＴＹＯＦＷＨＩＳＫＥＲＳＡＮＤＩＮＴＥＲＦＡＣＩＡＬＭＩＣＲＯＳＴＲＵＣＴＵＲＥＩＮＡＬＵＭＩＮＵＭＭＡＴＲＩＸＣＯＭＰＯＳＩＴＥＳＲＥＩＮＦＯＲＣＥＤＢＹＫ_２Ｏ·８ＴｉＯ_２ＷＨＩＳＫＥＲＳ￥ＬＩＪｉｈｏｎｇ;ＮＩＮＧＸｉａｏｇｕａｎ...     

RHEOLOGICAL PROPERTIES OF METAL INVECTION MOLDING BINDER AND FEEDSTOCK

ＲＨＥＯＬＯＧＩＣＡＬＰＲＯＰＥＲＴＩＥＳＯＦＭＥＴＡＬＩＮＶＥＣＴＩＯＮＭＯＬＤＩＮＧＢＩＮＤＥＲＡＮＤＦＥＥＤＳＴＯＣＫ①ＬｉＹｉｍｉｎ，ＱｕＸｕａｎｈｕｉ，ＨｕａｎｇＢａｉｙｕｎ，ＱｉｕＧｕａｎｇｈａｎＮａｔｉｏｎａｌＫｅｙＬａｂｏｒａｔｏｒｙ...     

MAGNETIC ACOUSTIC EMISSION CHARACTERISTICS OF HYDROGEN ATTACKED LOW CARBON STEEL

ＭＡＧＮＥＴＩＣＡＣＯＵＳＴＩＣＥＭＩＳＳＩＯＮＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＨＹＤＲＯＧＥＮＡＴＴＡＣＫＥＤＬＯＷＣＡＲＢＯＮＳＴＥＥＬ￥ＬＩＨｉａｏｇａｎｇ;ＭＥＮＧＱｉｎｇｈａｉ;ＣＨＥＮＨｕａ;ＣＨＥＮＪｉｎｗｅｉ;ＹＡＯＺｈｉｍｉｎｇ;...     

DETERMINATION OF STATES OF STRESS AND STRAIN AT POLE OF HYDRAULIC BULGE ORTHOTROPIC SHEET SAMPLE

ＤＥＴＥＲＭＩＮＡＴＩＯＮＯＦＳＴＡＴＥＳＯＦＳＴＲＥＳＳＡＮＤＳＴＲＡＩＮＡＴＰＯＬＥＯＦＨＹＤＲＡＵＬＩＣＢＵＬＧＥＯＲＴＨＯＴＲＯＰＩＣＳＨＥＥＴＳＡＭＰＬＥ￥Ｚｈｏｕ，Ｗｅｉｘｉａｎ；Ｚｈｏｕ，Ｘｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＡｅｒｏｎａｕｔ...     

CATALYTIC EFFECT OF FORMIC ACID UPON AMORPHOUS CHROMIUM ELECTRODEPOSITION

ＣＡＴＡＬＹＴＩＣＥＦＦＥＣＴＯＦＦＯＲＭＩＣＡＣＩＤＵＰＯＮＡＭＯＲＰＨＯＵＳＣＨＲＯＭＩＵＭＥＬＥＣＴＲＯＤＥＰＯＳＩＴＩＯＮＷａｎｇＸｉａｎｙｏｕ；ＪｉａｎｇＨａｎｙｉｎｇ；ＧｕｏＢｉｎｇｋｕｎ（ＩｎｓｔｉｔｕｔｅｏｆＭｅｔａｌｌｕｒｇｉｃａｌ...     

Lattice correspondence during twinning in hexagonal close-packed crystals

The correspondence of the dominant slip modes in parent and twin structures in hexagonal closed-packed crystals is considered within the framework of the theory of deformation twinning. The correspondence matrices, which provide a link between the parent and twin lattices, have been worked out for compound twinning modes and selected metals. Geometrical considerations suggest that in most cases deformation twins should inherit a harder dislocation substructure than that of the corresponding parent. Possible mechanisms of twin hardening are discussed.     

纳米面心立方金属的变形机制及影响其力学性能的因素

综述了纳米面心立方金属的变形机制随晶粒尺寸的减小而发生的变化,即变形机制由晶界处发射不全位错、形成孪晶转变为晶界滑移、晶粒转动.当变形机制为晶界处发射不全位错、形成孪晶时,存在最佳孪晶形成晶粒尺寸范围,此时的孪晶形核应力最小.另一方面,随着晶粒尺寸的减小,在变形机制发生转变的临界晶粒尺寸附近存在韧-脆断裂方式的转变.提高孪晶密度、在纳米晶材料中加入微米晶相形成双峰晶粒材料可以提高纳米晶材料的塑性,得到更好的综合机械性能.     

Plastic deformation mechanism in nanotwinned metals: An insight from molecular dynamics and mechanistic modeling

An overview is given of the deformation mechanisms in nanotwinned copper, as studied by recent molecular dynamics, dislocation mechanics and crystal plasticity modeling. We highlight the unique role of nanoscale twin lamellae in producing the hard and soft modes of dislocation glide, as well as how the coherent twin boundaries affect slip transfer, dislocation nucleation, twinning and detwinning. These twin boundary-mediated deformation mechanisms have been mechanistically linked to the mechanical properties of strength, ductility, strain hardening, activation volume, rate sensitivity, size-dependent strengthening and softening in nanotwinned metals. Finally, discussions are dedicated to identifying important unresolved issues for future research.     

Twinning during hot compression of ZK30 ＋ 0.3Yb magnesium alloy

The twinning process of ZK30＋0.3Yb magnesium alloy was studied. The results show that twinning occurs at the initial stage of deformation, and decreases during further deformation. The original grain is fragmented after small straining. It is investigated that the twinning boundary activates the occurrence of the non-basal slip system due to the stress concentration at the vicinity of twin boundary introduced by the dislocation pile-ups at the vicinity of twinning boundary. The rearrangement of dislocation after dislocation climb introduces new grain boundary. Simultaneously, twinning occurs to form “polygonization” due to the stress concentration relaxation, and the “polygonization” will transform into low angle boundary to refine the original grain under the shear stress with further straining.     

Deformation twinning in bulk nanocrystalline metals: Experimental observations

Deformation twins have been observed in nanocrystalline (nc) fcc metals with medium-to-high stacking fault energies such as aluminum, copper, and nickel. These metals in their coarse-grained states rarely deform by twining at room temperature and low strain rates. Several twinning mechanisms have been reported that are unique to nc metals. This paper reviews experimental evidences on deformation twinning and partial dislocation emissions from grain boundaries, twinning mechanisms, and twins with zero-macro-strain. Factors that affect the twinning propensity and recent analytical models on the critical grain sizes for twinning are also discussed. The current issues on deformation twinning in nanocrystalline metals are listed.     

In-situ TEM study of dislocation-twin boundaries interaction in nanotwinned Cu films

Epitaxial thin films of nanotwinned face-centered cubic metals such as Cu possess an unprecedented combination of high hardness and high electrical conductivity due to the unique structure of nanometer-spaced coherent twin boundaries. Recent studies of in-situ nanoindentation in a transmission electron microscope have provided new insights on the deformation behavior of nanotwins that are reviewed here. In particular, two unit processes are highlighted: first, stress-induced migration of Σ3 {112} incoherent twin boundary that leads to de-twinning of nanotwins; second, twinning dislocation can be multiplied at Σ3 {111} coherent twin boundary.     

低温轧制纯锆的形变孪晶及织构演变

通过在77K温度下进行不同变形量的低温轧制实验,研究了具有强烈单轴织构的工业纯锆板材在低温轧制变形条件下的孪生行为及变形机理。采用扫描电镜（SEM）和电子背散射衍衬（EBSD）分析和表征了变形材料的微观组织和织构。结果表明,在沿C轴加载的低应变条件下{1022}〈1123〉压缩孪生是主要的变形机制,同时在{1022}〈1123〉压缩孪晶中产生了二次孪晶（{10}-2}〈10T1〉拉伸孪晶）以协调变形。施密特因子计算及孪晶分布的EBSD模拟结果表明,在低温变形条件下的孪生模式的选择是由施密特因子的数值大小决定的。探讨并解释了轧制过程中随着应变量增加由孪生所导致的织构演变。     

Interfacially Driven Deformation Twinning in Bulk Ag-Cu Composites

Interfaces and interface/defect interactions increasingly dominate the mechanical response of materials as the dimensions of the grains decrease to the nanoscale. Recently, we reported unusually profuse deformation twinning in Ag-Cu layered eutectic composites with bilayer thicknesses in the submicron regime (~200?nm?C400?nm) at room temperature and low strain rates. Using atomistic simulations and dislocation theory, we propose that the Ag-Cu interface facilitated deformation twinning in Cu by permitting the transmission of twinning partials from Ag to Cu. In this way, twins in Ag can provide an ample supply of twinning partials to Cu to support and sustain twin growth in Cu during deformation. Interface-driven twinning as revealed by this study suggests the exciting possibility of altering the roles of dislocation slip and twinning through the design of heterophase interface structure and properties.