国产精品亚洲а∨怡红院,亚洲最大成人网 色香蕉,亚洲乱亚洲乱少妇无码,久久久久国产a免费观看rela

常州精密鋼管博客網(wǎng)

純金屬的塑性變形



  Stress-strain curve of mild steel

Plastic deformation is a permanent unrecoverable deformation. When the load that caused the deformation is removed, the material will not return to its original shape but will maintain its newly deformed shape.

Plastic deformation and the following heat treatment have significant effects on the microstructures and properties of materials, especially metal materials.

Therefore, it is important to understand the mechanism of plastic deformation and the effect of plastic deformation on the microstructures.

(1) Plastic Deformation of Single Crystals and Strain Strengthening單晶體的塑性變形及應變強化

Plastic deformation of a single crystal metal. (a) schematic illustration of normal and shear stresses on a plane when a pure tensile force is applied. (b) schematic illustration of plastic deformation due to the shear stress τ. (c) a photography of a plastically deformed zinc single crystal. 


A single crystal can be deformed by the application of a tensile force F

Tensile stress σ (正應力):may cause elastic deformation and cleavage fracture

Shear stress τ (切應力):may result in slip, and consequently plastic deformation



               The mechanism of plastic deformation for most metals is slip and twinning. 


Slip takes place only under shear stress. 

The slip deformation forms small steps on the surface of the single crystal, which is termed slip band


The slip planes are usually the most densely packed planes(密排面); the slip directions are usually close-packed directions(密排方向).

A combination of the slip plane and the slip direction is termed the slip system. 

The slip system depends on the crystal structure.

                                       Slip systems for FCC,BCC and HCP structures

     The figure shows schematically an edge dislocation moves in response to a shear stress and produce a unit of slip under a low shear stress.  It can be seen that only a small group of atoms slip over each other at any particular instant.



Twinning occurs in a specific direction called the twinning direction. The displacement magnitude within the twin region is proportional to the distance from the twin plane.




Comparing with slip, twinning requires relatively large shear stress, and the deformation by twinning is very fast.

Twinning easily takes place in HCP crystal structures because there are few operable slip systems. In FCC structure, there is generally no twinning deformation. The twin structure observed in FCC structure usually is the result of phase transformation during an annealing heat treatment, which is called annealing twin(退火孿晶).

(2)  Plastic Deformation of Polycrystalline Metals 多晶體金屬的塑性變形


There are grain boundaries between the grains. Moreover, because the orientations of the grains are different from each other, the direction of slip varies from one grain to another. For each grain, dislocation motion occurs along the slip system.

During plastic deformation under an external force, dislocations move to grain boundaries. If dislocations cannot traverse the grain boundaries, they tend to pile up at the grain boundaries.

Plastic deformation cannot occur in all the grains at the same time. Polycrystalline metals are stronger than their single crystal equivalents.

The procedure of plastic deformation of a polycrystalline metal

When an external force is applied on a polycrystalline metal and plastic deformation occurs, slip first takes place in the grains, in which the angle between the slip system and the external force direction is close to 45°. The dislocation pileups introduce stress concentrations ahead of the slip planes.

When this stress increases to a certain level, the dislocations in adjacent grains begin to glide. When slip occurs in a large amount of grains, the specimen of polycrystalline metal shows plastic deformation in macro scale.

圖片加載中...
? 請關(guān)注 微信公眾號: steeltuber.
 轉(zhuǎn)載請保留鏈接: http://gzsunfar.com/Steel-Knowledge/Plastic-deformation-of-pure-metals.html
(本平臺"常州精密鋼管博客網(wǎng)"的部分圖文來自網(wǎng)絡轉(zhuǎn)載,轉(zhuǎn)載目的在于傳遞更多技術(shù)信息。我們尊重原創(chuàng),版權(quán)歸原作者所有,若未能找到作者和出處望請諒解,敬請聯(lián)系主編微信號:steel_tube,進行刪除或付稿費,多謝!)
搜索本站鋼鐵技術(shù)
★↓在此搜索查找鋼鐵材料知識↓★↘

互聯(lián)網(wǎng) gzsunfar.com


鋼鐵行業(yè)熱點文章推薦

常州精密鋼管博客網(wǎng)主辦單位:
常州仁成金屬制品有限公司 是 專業(yè)的 精密鋼管 生產(chǎn)廠家,汽車鋼管,電機殼鋼管 生產(chǎn)單位。


常州精密鋼管博客網(wǎng)推薦您訪問:

常州精密鋼管博客網(wǎng)
(常州仁成金屬鋼管制品生產(chǎn)廠家博客網(wǎng)站)
gzsunfar.com?2006-2021
蘇ICP備08003692號

【關(guān)于本站】【提問】網(wǎng)站地圖【搜索】【知識星球】電腦端

被灌满精子的少妇视频| 国产精品va尤物在线观看蜜芽| 亚洲 一区二区 在线| 动漫人妻h无码中文字幕| 国产精品天天看特色大片| 免费特黄夫妻生活片| 久艹视频免费看| 色欲综合久久躁天天躁蜜桃| 美女av一区二区三区| 亚洲va欧美va人人爽| 少妇午夜福利一区二区| 国产精品久久国产精麻豆99网站| 久久这里只有精品18| 综合一区无套内射中文字幕| 免费看又色又爽又黄的国产软件 | 九九热视频在线精品18| 白嫩少妇喷水正在播放| 欧美亚洲国产成人一区二区三区| 国产精品久久久久久麻豆一区| 人人妻人人爽人人澡av| 乱熟女高潮一区二区在线| 女人天堂一区二区三区| 亚洲中文字幕无码一区在线| 日韩精品一区二区午夜成人版| 一本色道久久88—综合亚洲精品| 国产美女露脸口爆吞精| 国产∨亚洲v天堂无码久久久| 尤物yw午夜国产精品大臿蕉| 国产愉拍91九色国产愉拍| 久久久国产99久久国产久一| 亚洲成a人片在线观看无码专区 | 中文字幕 在线观看 亚洲| 国产亚洲产品影市在线产品| 欧美丰满熟妇xx猛交| 18禁成年免费无码国产| 国产真实乱子伦精品视频| 国产成人无码a区在线观看导航 | 丝袜人妻一区二区三区| 国产亚洲精品a在线观看下载| 亚洲精品欧美二区三区中文字幕| 99久久精品费精品国产一区二|