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摘要超细晶材料具有优异的性能，其制备方法通常包括高压扭转法、叠层轧合技术、反复折皱-压直法、等径角挤压变形法及多向锻压法等。其中 ECAP变形技术由于作为许多材料获取超细晶组织以来提高其力学性能的的方便手段，因而近年来受到了极大的关注。如今对纯铜 ECAP 加工变形领域的研究已经取得许多进步和成果。然而，尽管在该领域已有大量研究，与 ECAP 的其他方面相比，对纯铜ECAP 变形态热处理过程中织构的变化的了解却甚少。本毕业论文研究了无氧纯铜（纯度 99.98%）在采用 Bc 方式经过 8 道次 ECAP 加工变形及随后热处理后的显微组织和织构的变化。在 ECAP 变形后，试样分别置于不同温度下和不同时间变量条件退火处理。变形状态和退火后状态的试样经过 EBSD、TEM以及硬度测试。其织构的形成和显微组织的变化被记录下来并与冷轧材料中织构的形成和显微组织的变化进行了对比。我们对观察的现象进行了分析，认为这些现象与再结晶及晶粒生长机理有关。结果显示在随后的退火中，织构和显微组织的变化与非连续再结晶有关。该研究说明 ECAP加工后的纯铜具有非常低的热稳定性。19199
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关键词 超细晶 等径角挤压 织构 再结晶
Title The Preparation of Ultra-fine Grained Copper and the Study in its Thermal Stability
Abstract
Ultra-fine grain materials have excellent properties, and the methods of
preparation usually include High Pressure Torsion、Accumulative Roll
bonding、Repetitive Corrugation and Straightening、Equal Channel Angular
Pressing、Multi-directional Forging etc. ECAP deformation received great
attention in recent years since it provides a convenient way to obtain
ultra-fine grain for many materials to improve the
mechanical properties. Recently much progress and achievements has been
made in the field of ECAP deformation of pure copper. However, although
a number of studies have been made in the field, compared with other aspects
of ECAP, Comparatively little is known about the mechanisms of
microstructural change during annealing. Microstructure and texture
evolution of pure copper (99.98%) after equal-channel angular pressing
(ECAP) with route Bc up to 8 passes and subsequent heat treatment were
investigated.After ECAP deformation, samples under different temperatures
and different annealing-treatment time are studied. The deformed and
annealed states were characterized by X-ray pole figures, electron back
scatter diffraction (EBSD), TEM and microhardness tests. The formation of
the texture and the change of microstructure were recorded and compared
with texture of cold rolled material formation and the changes of
microstructure were compared. We analyzed the phenomenon of
observation and think that these phenomenon related to the
recrystallization and grain growth mechanism. Results show that in the
subsequent annealing, texture and microstructure changes related to the
discontinuous recrystallization. The study shows that after ECAP
processing pure copper has a very low thermal stability.
Keywords Ul tra-fine grain ECAP Texture Recrystalization
目录
1 绪论 1
1.1 引言 . 1
1.2 剧烈塑性变形 . 1
1.2.1 高压扭转法 . 2
1.2.2 反复折皱-压直法 3
1.2.3 ECAP 变形法. 3
1.3 纯铜 ECAP 变形的组织与性能特点 5
1.4 ECAP 超细晶铜的研究现状. 7
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