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谁非金属材料专业英语好帮翻译一下
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3.4 Linear and Planar Defects 3.4.1 Dislocations -Linear Defects Dislocations* are line imperfections in an otherwise perfect lattice. We can identify two types of dislocations - the screw dislocation* and the edge dislocation*. The screw dislocation (Figure 13) can be illustrated by cutting partway through a perfect crystal, then skewing the crystal one atom spacing. Figure 13 Screw dislocation If we were to follow a crystallographic plane one revolution around the axis on which the crystal was skewed, traveling equal atom spacings in each direction, we would finish one atom spacing below 13 point. [l] The vector required to complete the loop and return us to our starting point is the Burgers vector* b. If we continued our rotation, we would trace out a spiral path. The axis, or line, around which we trace out this path is the screw dislocation. We see that the Burgers vector is parallel to the screw dislocation. An edge dislocation (Figure 14) can be illustrated by slicing partway through a perfect crystal, spreading the crystal apart, and partly filling the cut with an extra plane of atoms. The bottom edge of the inserted plane represents the edge dislocation. If we describe a clockwise loop around the edge dislocation by going an equal number of atom spacings in each direction, we would finish one atom spacing from our starting point. The vector that is required to complete the loop is again the Burgers vector. In this case, the Burgers vector is perpendicular to the edge dislocation. Figure 14 Edge dislocation 3.4.2 Surface Defects Surface defects are the boundaries that separate a material into regions, each region having the same crystal stmcture but different orientations. Grain Boundaries The microstructure of metals and many other solid materials consists of many grains. A grain is a portion of the material within which the arranement, or crystal structure, is different for each adjoining grain. A grain boundary* is the surface that separates the individual grains and is a narrow zone in which the atoms are not properly spaced. A grain boundary is represented schematically from an atomic perspective in Figure 15. Within the grain boundary region, which is probably just several atom distances wide, there is some atomic mismatch in a transition from the crystalline orientation of one grain to that of an adjacent one.[2] Figure 15 Grain boundaries Figure 16 Small-angle grain boundary Various degrees of crystallographic misalignment between adjacent grains are possible. When 14 this orientation mismatch is slight, on the order of a few degrees , then the term small- ( or low - ) angle grain boundary * is used. These boundaries can be described in terms of dislocation arrays. One simple small-angle grain boundary is formed when edge dislocations are aligned in the manner of Figure 16. This type is called a tilt boundary.* Twin Boundaries* A twin boundary is a plane across which there is a special mirror image misofientation of the lattice structure (Figure 17). Twins can be produced when a shear force, acting along the twin boundary, causes the atoms to shift out of position. Twinning occurs during deformation or heat treatment of certain metals. The twin boundaries increase the strength of the metal. Figure 17 Twin boundary Key words: dislocation [ 位错 ] screw dislocation [螺形位错] edge dislocation [刃形位错] Burgers vector [柏氏矢量] spiral [ 螺旋形的 ] grain boundary [晶界] small- (or low-) angle boundary [小角度晶界] tilt boundary [倾侧晶界] twin boundary [孪晶界] Questions: 1) Is the Burgers vector perpendicular to the screw dislocation? 2) What is a twin boundary? 3.5 Non-crystalline* Materials Non-crystalline solids lack a systematic and regular arranagement of atoms over relatively large atomic distances. Sometimes such materials are also called amorphous, or supercooled liquids, inasmuch as their atomic structure resembles that of a liquid. An amorphous condition may be illustrated by comparison of the crystalline and non-crystalline structures of the ceramic compound silicon dioxide (SiO2), which mayexist in both states. Figure 18 (a) and (b) present two-dimensional schematic diagrams for both structures of SiO2, in which the SiO4 4- tetrahedron is the basic unit. Even though each silicon ion bonds to four oxygen ions for both states, beyond this, the structure is much more disordered and irregular for the non-crystalline structure. Whether a crystalline or amorphous solid forms depends on the ease with which a random atomic structure in the liquid can transform to an ordered state during solidification. [1] Amorphous materials, therefore are characterized by atomic or molecular structures that are relatively complex and become ordered only with some difficulty. Furthermore, rapidly cooling through the freezing temperature favors the formation of a 15 non-crystalline solid, since little time is allowed for the ordering process. Metals normally form crystaUine solids; but some ceramic materials are crystalline, whereas others are amorphous. Polymers may be completely non-crystalline and semi-crystalline consisting of varying degrees of crystallinity*. (a) Crystalline silicon dioxide (b) Non-crystalline silicon dioxide Figure 18 Two-dimensional schemes of the structure of silicon dioxide Key words: non-crystalline[ 非晶的] crystallinity [ 结晶度] 3. 6 Microstructure When describing the structure of a material, we make a clear distinction between its crystal structure and its microstructure. The term "crystal structure" is used to describe the average positions of atoms within the unit cell, and is completely specified by the lattice type and the fractional * coordinates of the atoms. [1] In other words, the crystal structure describes the appearance of the material on an atomic length scale. The term "microstmcture" is used to describe the appearance of the material on the nm-cm length scale. A reasonable working definition of microstmcture is "the arrangement of phases and defects with a material." Many times, the physical properties and, in particular, the mechanical behavior of a material depend on the microstmcture. Microstmcmre is subject to direct microscopic observation, using optical or electron microscopes. In many alloys, microstmcture is characterized by the number of phases present, their proportions, and the manner in which they are distributed or arranged. The microstmcture of an alloy depends on such variables as the alloying elements present, their concentration, and the heat treatment of the alloy. 3.6.1 Phase Diagrams* Much of the information about the control of microstrucmre or phase structure of a particular alloy system is conveniently and concisely displayed in what is called a phase diagram, also often termed an equilibrum or constitutional diagram. Many microstrucmres develop from phase transformation, the changes that accur between phases when the temperature is altered (ordinarily upon cooling). This may involve the transition from one phase to another, or the apace or disappearance of a phase. Phase diagrams are helpful in predicting phase transformations and the resulting microstmctures, which may have equilibrium or nonequilibrium character. |
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【工具翻译，意思对，自己整理】 3.4直线和平面缺陷 3.4.1位错线性缺陷 位错*正处在一个美中不足格线的缺陷。我们可以识别两种类型的 混乱-螺杆脱位*和刃型位错*.的螺位错（图13）可 加以说明，贯穿中途一个完美的晶体，晶体则撰文指出，一个原子间距。 图13螺杆脱位 如果我们遵循结晶飞机一轴各地革命的结晶 被人做了手脚，旅行，每个方向原子间距相等，我们会完成下面一个原子间距 13 点。 [升]需要完成的循环，我们回到我们的出发点的向量是汉堡包 矢量*湾如果我们继续轮换，我们将描绘出一个螺旋路径。轴，或行，约 我们描绘出这条道路是螺位错。我们看到，Burgers矢量平行于 螺位错。一个刃型位错（图14），可以从通过中途切片 完美的晶体，晶体传播外，部分填补了一个额外的原子平面晋级。那个 插入的飞机底部边缘代表刃型位错。如果我们描述一个顺时针循环 由各地要对每个方向相同数目的原子间距刃型位错，我们会 完成从一个原子间距我们的出发点。矢量所需完成循环 再次汉堡包载体。在这种情况下，Burgers矢量垂直于刃型位错。 图14边缘脱位 3.4.2表面缺陷 表面缺陷的界限，将另1到区域，每个区域的物质具有 水晶stmcture相同，但不同的方向。 晶界 的金属微观组织和许多其他固体材料包括很多粮食。阿粮食是 1材料在其中arranement，或晶体结构，为每个不同的部分 毗邻粮食。甲晶界*是表面的单个颗粒的分离，是一个狭窄 区域中的原子间距不正确。甲晶界的代表从图式 在图15原子的观点。晶界内的区域，这可能只是几个 原子的距离宽，有一些从结晶方向过渡原子错配 1粮食认为相邻1 [2]。 图15图16晶界小角晶界 相邻晶粒之间不同程度的晶体偏差是可能的。何时 14 这个方向是轻微的不匹配，在几度的命令，那么长期小（或低- ） 角度晶界*使用。这些界限，可以说在阵列上的混乱。一个 简单的小角度晶界的位错时形成的优势是在对齐方式 图16。这种类型称为倾斜边界.* 双边界* 阿孪晶界是一个平面上的有一个特别的镜像图像misofientation 晶格结构（图17）。双胞胎可以生产剪切力时，沿孪晶界采取行动， 导致原子转移出来的位置。结对发生在变形或热处理 某些金属。这两个边界增加金属的强度。 图17双边界 关键词: [ 位错 ] [螺形位错] [刃形位错] [柏氏矢量] [ 螺旋形的 ] [晶界] [小角度晶界][倾侧晶界] [孪晶界 问题： 1）是否柏格斯矢量垂直螺位错？ 2）什么是孪晶界？ 3.5非结晶*材料 非结晶固体缺乏对相对较大的原子系统和经常arranagement 原子的距离。这种材料有时也称为无定形，或过冷液体， 因为它们的原子结构类似于液体。无定形状态可能会 说明了对陶瓷复合材料，结晶和非结晶结构的比较 二氧化硅（SiO2），这两种状态mayexist。图18（a）和（二）目前的二维 双方的二氧化硅结构，原理图，其中的硅氧 4 -四面体为基本单位。偶数 尽管每个硅离子债券，这两个州的四个氧离子，除此之外，大部分的结构 更多的无序和非晶体结构不规则。是否结晶或无定形 固体形式取决于难易程度随机在液态原子结构可以改变一个 在凝固过程中有序状态。 [1]非晶材料，所以特点是原子或 这是比较复杂，而成为有一些困难分子结构排列的。 此外，通过快速冷却主张冻结温度的形成 15 非结晶固体，因为几乎没有时间为订购过程允许的。金属一般形式 crystaUine固体;但有些陶瓷材料的晶体，而另一些无定形。聚合物 可能是完全的非结晶和半结晶不同组成 结晶度*. （1）结晶二氧化硅（b）非结晶二氧化硅 图18二维计划的硅结构的二氧化碳 关键词： 非结晶[非晶的]结晶[结晶度] 3。 6显微 当描述一个物质结构，我们提出了晶体之间的明确区分 结构和微观结构。术语“晶体结构”是用来描述平均排名 原子晶胞内，是完全由格类型指定和小数* 坐标原子。 [1]换言之，晶体结构，描述了外观 材料原子尺度。术语“microstmcture”用来描述外观 纳米材料的厘米长的规模。一个合理的工作microstmcture的定义是“ 安排的材料。阶段和缺陷“ 安排的材料。阶段和缺陷“ 很多时候，和物理性质，特别是材料力学行为 取决于microstmcture。 Microstmcmre是受直接显微镜观察，使用光学 或电子显微镜。在许多合金，microstmcture的特点是数量的阶段 目前，他们的比例，以及它们的分布和排列方式。那个 一种合金microstmcture取决于作为合金元素目前，这种变数的 浓度和合金的热处理。 3.6.1相图* 大部分关于microstrucmre或某一阶段的结构控制信息 合金系统是方便，简洁，在一个所谓的相图显示，也常常 所谓均衡或宪法图。许多microstrucmres发展的阶段 转型，改变各相accur当温度改变（通常要求 冷却）。这可能涉及到另一个从一个过渡阶段，或迅速进行或失踪 阶段。相图，有助于预测相变以及由此microstmctures， 可能有平衡或非平衡性。 |
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