裂纹

Based on analyzing and summing up the study results on deformation and fracture mechanisms of materials and member under repeated impact load,this paper shows that material defomation is characterized by plastic deformation concentrating on impact point,multi-systemes sliping difficult to perform and strain more unhomogeneous.

本文综合归纳了材料和构件在循环冲击载荷下的变形、断裂规律及机理研究成果，指出材料的变形具有多系滑移难于进行、应变不均匀性大和塑性变形集中在冲击接触点的特点；材料断裂过程为裂纹萌生、扩展和最后断裂过程，组织及实验条件对材料断裂有较大影响。

Exerting surrounding pressure can prevent crack growing in a uniaxially compressed concrete specimen. The behavior of concrete in which there is no crack propagation (called ideal state without damage growth) is researched in this paper.

通过对混凝土施加围压，使单轴受压混凝土的裂缝发展受到限制，从而研究混凝土在接近无裂纹发展状态下的受压性能。

The uniphase C with W/≤0.3 can be synthesized without being preheated. When W/ is higher than 0.3, the sample expansion increases with the increase of W content, the reaction between W and C is incomplete, the combustion products consist of W〓C, WC, TiC, C, and unreacted W. Preheating mixtures can accelerate the completion of the reaction among Ti, W, and C. The uniphase C with W/=0.4 can be synthesized by SHS at preheat temperature of 600℃. There are two kinds of powders with size of 2-4μm and size less than 1μm in the combustion products.

通过燃烧前沿激冷淬熄试验及产物形貌特征（燃烧块断面组织和产物多晶聚合体颗粒）分析，创新性地提出了两种体系的自蔓延高温反应机制。1熔化—溶解—析出机制：当燃烧温度较高时，燃烧前沿Ti粉熔化，W和C溶解于熔融Ti里，而后C从熔融里析出。2扩散—固溶机制：当燃烧温度不足以使燃烧前沿Ti粉熔化时，通过C的扩散先形成TiC层，其后C沿着热应力导致的TiC层裂纹继续扩散，与固态Ti核反应生成TiC；同时，C扩散至W颗粒，形成W〓C，而后通过C的继续扩散W〓C转变成WC；与此同时，WC固溶至TiC里，形成C固溶体。

At lower normal loads, the composites exhibit wear resistance superior to that of SiCw/6061Al composite under unlubricated sliding friction conditions.

对低Al含量的复合材料，由于Al〓O〓颗粒的存在强化了Al〓Ti相的晶界，增加了Al〓Ti解理裂纹扩展阻力，同时位错强化和细晶强化也对强度有一定贡献；对以Al为主要相的复合材料，兼有位错强化、固溶强化、细晶强化和弥散强化多种机制。

Unstressed specimen, which is due to hydrogen concentration in bended specimen is higher.

利用裂纹面分离及SEM和EDS研究了L360MCS钢焊接热影响区在湿H2S环境中的应力导向氢致开裂行为。

A region of tempered martcnsite with low hardness occurred farther beyond the untempered martensitic region and intergranular microcracks run perpen...

裂纹的发生是由于相变时不同的体积改变所造成的拉应力引起的，而相变是由于事故发生时的热冲击所导致。

The hardened case ununiformity and quenching cracks of H32058 driven ring gear after the medium frequency induction quenching were analyzed.

分析了H32058从动齿圈经中频淬火后出现的淬硬层分布不均和淬火裂纹等缺陷的原因，通过重新设计感应器和反复工艺调试，利用两次中频加热淬火方式实现预热中频淬火，获得了沿齿廓分布的淬硬层。

Such aspects as crack on surface of raw material, ununiformity of surface microstructure, bainite structure, composition segregation, severe inclusion are main cause for drawing fracture of steel wire rod for welding.

原料表面裂纹、表面组织不均、贝氏体组织、成分偏析、夹杂物严重是引起焊接用盘条拉拔断裂的主要原因。

Firstly the oxidation loss was controlled by the reaction between the coated C/C composites and oxygen. Secondly the oxidation loss was controlled by the producing and vaporing rate of the glass. The oxidation loss was lined with the oxidation time. Thirdly there were cracks in the coating and the deep of the coating was oxidated. The weight loss rate increased linearly and the matrix had been oxidated partly in the end.

氧化初期，涂层的表面开始氧化，氧化失重是一个受氧气和涂层的化学反应控制，表现为氧化增重；氧化中期，氧化失重受玻璃质的形成速度和蒸发速度控制，表现为缓慢的氧化失重，氧化失重与时间的关系为直线型；随后，涂层上出现裂纹的形成和愈合过程，涂层深层被氧化，表现为较快的氧化失重；最后，涂层被局部破坏，基体被部分氧化，氧化失重直线上升。

The bell was made in Whitechapel. The bell's tone is E flat – very flat, in fact, due to cracks in the bell

大本钟在伦敦Whitechapel区制造，大本钟的音调为E调，很纯的E调，是钟上的裂纹造成的。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。