ch2位错-2.4位错与晶体缺陷作用

strain field is lower ttion, they will
attract each other.
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➢ This leads to some simple cases: 1. Arbitrarily curved dislocations with identical b on the same glide plane will always repel each other.
Ch2 位错
2.1 位错理论的产生 2.2 位错的几何性质 2.3 位错的弹性性质 2.4 位错与晶体缺陷的相互作用 2.5 位错的动力学性质 2.6 实际晶体中的位错
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2.1 位错理论的产生
一、晶体的塑性变形方式 二、单晶体的塑性变形 三、多晶体的塑性变形 四、晶体的理论切变强度 五、位错理论的产生 六、位错的基本知识
If we start with screw dislocations, we have to distinguish the following cases:
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➢ In analogy, we next must consider the interaction of edge
dislocations, of edge and screw dislocations and finally of mixed
get everything from there.
➢ But for just obtaining some basic rules, we can do better than
that. We can classify some basic cases without calculating
anything by just examining one obvious rule:
more generally a 1/r dependence of the force on the
distance r between the dislocations.
For y < 0 or y > 0 we find zones of repulsion and
attraction. At some specific positions the force is zero -
dislocations.
The case of mixed dislocations - the general case - will again be
obtained by considering the interaction of the screw- and edge
parts separately and then adding the results.
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2.2 位错的几何性质
一、位错的几何模型 二、柏格斯矢量 三、位错的运动 四、位错环及其运动 五、位错与晶体的塑性变形 六、割阶
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2.3 位错的弹性性质
一、弹性连续介质、应力和应变 二、刃型位错的应力场 三、螺型位错的应力场 四、位错的应变能 五、位错的受力 六、向错 七、位错的半点阵模型
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2.4 位错与晶体缺陷的相互作用
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➢ The general formula for the forces between edge
dislocations in the geometry shown above is
➢ Fx = [Gb2 / 2p(1 –n)] ·[x ·(x2 – y2) /(x2 + y2)2 ] ➢ Fy = [Gb2 / 2p(1 –n)] ·[ y ·(3x2 + y2) /(x2 + y2)2 ] For y = 0, i.e. the same glide plane, we have a 1/x or,
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➢ 2. Arbitrary dislocations with opposite b vectors on the same glide plane will attract and annihilate each other
➢ Edge dislocations with identical or opposite Burgers vector b on neighboring glide planes may attract or repulse each other, depending on the precise geometry. The blue double arrows in the picture below thus may signify repulsion or attraction.
If the superposition of the strain fields of dislocations add up to
values of the compressive or tensile strain larger than those of a
single dislocations, they will repulse each other. If the combined
一、位错间的相互作用力 二、位错与界面的交互作用 三、位错与点缺陷的交互作用
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Interactions Between Dislocations
➢ We will first investigate the interaction between two straight and parallel dislocations of the same kind.
➢ With the formulas for the stress and strain fields of edge and
screw dislocations one can calculate the resolved shear stress
caused by one dislocation on the glide plane of the other one and