With increasing stress, small holes are created, gather, grow and finally become a crack that crossed ferrite grain. 微孔在应变应力作用下扩展,贯通,形成裂纹,穿过铁素体。
The results showed that the reasons of crack was of grain growth caused by improper heat treatment. 结果表明:裂纹是热处理不当造成晶粒长大所致。
The first principal normal stresses can lead to grinding crack which generates behind the abrasive grain in the plane perpendicular to grain motion. 在磨粒后方,受第一主应力的作用,产生垂直磨削方向的磨削裂纹。
In this paper, the reasons is analysed that cattle upper leather crack grain appears in process, and the relative precaution measures is put forword. 本文作者对黄牛皮鞋面革生产过程中产生裂面的原因进行了分析,并提出了相应的预防措施。
From the model, the critical effect tensile stress for the initiation of hydrogen induced crack along grain boundaries has been derived. 由该模型推导出氢致沿晶裂纹萌生时的临界有效拉应力。
Cu-based shape memory alloys possess low price, good thermal stability and the property of high temperature application. But intergranular crack and grain coarseness are its technology issues retarding practical application. 铜基形状记忆合金具有价格低廉、热稳定性好和高温应用前景等优点,然而晶间断裂和晶粒粗大是其目前未得到实用化的技术关键。
In order to ensure solid motor with cracked grain to be successfully launched, the strain and stress concentration at the tips of crack should be released by shoveling slot on the crack of grain surface. 工程实际中通常采用于药柱表面裂纹处铲槽的方法来释放裂纹尖端的应力应变集中,以确保药柱含裂纹的固体发动机能正常点火发射。
Stability Analysis of the Surficial Crack of Solid Missile Motor Grain 固体导弹发动机药柱表面裂纹稳定性分析
The shielding effect from grain boundary was found in the test for grain cracked bicrystals with the crack normal to the grain boundary. 在晶界垂直晶粒裂纹的双晶体试验中,揭示了晶界对晶粒断裂的屏蔽效应:当裂纹距晶界某一特定长度时,断裂韧性值最大。
Discussion about methods of preventing crack grain of cattle upper leather 解决牛鞋面革皮坯裂面的方法试探
Abstract How to conduct the technological control in production of yak hide upper leather from soaking to drying, in order to prevent and overcome the problems of loose grain and crack grain are the main subject described in this paper. 本文介绍了在牦牛皮回革生产中,从浸水到干燥,应如何进行工艺技术控制,以防止和克服松面、裂面。
Development of crack are along grain boundary. 裂纹的形成除初始裂纹外,冲击时裂纹首先沿着颗粒张开;
With the increase of carbon content, the quantity of primarily chromium and molybdenum carbide increased while the wear resistant decreased because the crack sprout in grain boundary at where the carbides formed and the flaking is the main wear mechanism in the impact process. 继续提高碳含量,晶界处以铬钼为主碳化物的量增加,冲击过程中裂纹在该处萌生,产生剥落现象,造成耐磨性下降。
For the ZrB_2/ SiC ceramic, strengthening mechanisms is grain refining and the toughening mechanism is crack deflection/ decomposition and grain refining. ZrB2/SiC的强化机制是晶粒的细化,韧化机制是裂纹的偏转/分解和晶粒的细化。
The Using of Singular Crack Elements in Crack Analysis of Solid Missile Motor Grain 奇异裂纹单元在固体导弹发动机药柱裂纹分析中的应用
Investigating progress of hydrogen release during plastic deformation and hydrogen diffusivity under high vacuum, hydrogen distribution in hulks and hydride formation at crack tips, hydrogen segregation at grain boundaries and quantitative hydrogen analysis have been presented using Secondary Ion Mass Spectroscopy ( SIMS). 本文介绍了二次离子质谱技术对于塑性形变过程中氢释放和高真空下氢扩散率,体内氢分布和裂尖氢化物形成,晶界氢偏析和定量氢分析等方面的研究进展。
On the basis of the tests, this paper discussed the fracture behaviour of the para-macroscopic concrete which include crack tip, grain boundary, defect and nearby aggregates. 本文以实验为手段,讨论了混凝土准宏观局部断裂特性,这里的准宏观包括缝尖、界面、缺陷以及数个骨料构成的区域。
The Realization of Solving the Loose Grain and Crack Grain Problems in Yak Hide Leather Production 解决牦牛面革松面和裂面的实践体会
The mechanisms of grain bending, grain delamination, crack deflection inside the layered grain, crack deflection and branch, pull out grain are main energy absorbing mechanisms. 主要能量吸收机制为:晶粒的弯曲、层间滑移,裂纹在层间扩展与偏转,裂纹在晶粒间沿晶界扩展、分叉和晶粒的拔出。
SEM and metallographic analysis indicate that the crack grows along grain boundaries by cavitation. 扫描电镜和金相照片分析说明,裂纹沿晶界孔洞扩展。
An Investigation on the Relation between the Fatigue Crack Propagation Threshold and Grain Size The Application of the Dislocation Theory 疲劳裂纹扩展门槛值与晶粒尺寸关系的研究&位错理论的应用
It has been found that the occurrence of intergranular SCC was attributed to both electrochemical corrosion and localized stress concentration at chromium depleted grain boundaries, thus crack initiation and propagation along grain boundaries were accelerated. 研究表明:晶间型应力腐蚀破裂的产生是由于电化学腐蚀与局部应力同时集中在晶界贫铬区,加速裂纹始发并沿晶扩展所致。
The results reveal that the crack growth rates strongly depends on grain size and carbide distributin, and the creep crack growth rates are reversely relative to grain size. 结果表明晶粒尺寸和碳化物结构显著影响蠕变裂纹扩展速率,蠕变裂纹扩展速率与晶粒尺寸成反比关系。
Grain rotation which produces crack on the grain boundary was caused by force couple because slip is obstructed and stress concentrated on the grain boundary; 滑移在品界受阻产生应力集中并产生力偶使晶粒发生相对转动,从而在品界产生裂纹;
For notched specimen, the critical event of cleavage fracture determined by ferrite grain size is the propagation of a grain-sized crack into a neighboring grain. 对于缺口试样,铁素体晶粒尺寸对材料的解理断裂起决定性作用,临界事件是:铁素体晶粒尺寸的微裂纹扩展进入相邻的铁素体晶粒中。
Analysis and Precaution of Cattle Upper Leather Crack Grain 黄牛鞋面革裂面原因的分析与预防
Cohesive zone model was used to simulate two-dimensional plane strain crack propagation at the grain level model including grain boundary zones. 采用内聚力模型(CZM),模拟多晶体中起裂于晶界的二维平面应变裂纹扩展。
The more comprehensive analyses of the distribution of the density, hardness change, tensile strength, fracture type, fracture mode, crack expansion path, the average grain size, second phase distribution, grain boundary composition and so on were given. 较为全面的分析了制件的密度分布情况、硬度变化情况、抗拉强度、断裂类型、断裂模式、裂纹扩展模式、晶粒平均尺寸、第二相分布、晶界成分等内容。
The wedge crack forms as a result of grain boundary sliding. 在热疲劳过程中晶粒产生严重的滑动、转动。