裂纹

Results have shown that the predictions of statistic fracture with the distributional parameters determined by m...

结果表明，具有由微观途径确定裂纹分布参数的统计断裂的预测与实验观察值相符。

The microstructure of joints showed comparatively fine equiaxed grains and a narrow heat aff...

显微组织分析表明：搅拌摩擦焊接接头具有细小的等轴晶粒和狭窄的热影响区，阻碍了滑移带的形成和裂纹的扩展，从而提高了接头的疲劳性能。

After thermal cycling testing, when the strength of equiaxial grain regions or thermally grown oxidation layer became lower than the shear stress, the spallation occurred along the vertical crack network.

经过长时间热循环后，当陶瓷层等轴晶区的强度或者热氧化生长层的强度小于边缘效应产生的剪应力时，涂层在试样的中部以垂直裂纹网格形状发生剥落失效。

The results show that, by the way of optimizing preparation condition, the spherical zirconia powders with suitable particle size distribution are prepared using chemical precipitation method. Using heterogeneous chemical precipitation coating technique, the sph, erical nickel coated zirconia powders are prepared and the heterogeneous nucleation can be done on the surface of spherical zirconia powders. The thickness of coated layer, homogeneous degree and crack of surface can be controlled by the way of controlling powder concentration, adding rate of reactants feeding and adding surface active agent.

研究表明，采用化学沉淀法，通过优化制备工艺条件，可以制备粒径分布较均匀的球形氧化锆粉体；利用非均相化学沉淀包裹技术制备的金属镍包裹氧化锆微球粉体，球形氧化锆颗粒表面作为异相成核的场所，通过控制颗粒浓度、加料速度以及添加表面活性剂等工艺条件，可以调控包裹层厚度、表面均匀度以及表面裂纹等。

It was also found that the protecting effect of erodents on the coating surface does exist. The protecting effect will be more evident if using erosion efficiency of unit mass erodent of sand in the slurry to describe the erosivity of erodent. Besides a model is proposed to explain the protection process. The wear mechanism of the coating is the co-operation of ploughing, cracking and ablation.

对涂层的SEM分析可知，除冲蚀粒子在涂层表面的犁沟作用，冲蚀磨损的结果造成涂层的表面生成了系列针孔，其中的一部分为溶剂挥发所至，另外还存在由增强颗粒的剥落和裂纹的扩展造成的涂层剥落产生的孔洞，这将可能为水的吸收和扩散造成有利条件，使复合涂层亚表层产生内应力。

With air-formed films the faradaic processes decreased progressively to a constant rate consistant with the increase in potential, indicating the healing of surface flaws.

对于空气氧化膜，电化学反应速度逐步变慢，直至达到相应于稳定钝态的恒定值，同时电位向正移动，表明膜中的微裂纹不断得到修补。

During the first 10 hours the initial film dissolution was accompanied by a decrease in potential with an apparent plugging of flaws. However, after about 20 hours, the anodic film thickness decreased sufficiently to allow the faradaic processes toinerease to, the final steady state value.

开始时氧化膜比较厚，电化学反应主要局限在微裂纹内，由于阴极反应受抑止，电位变负；随着氧化膜减薄，电位变正，电化学反应速度加快，最后进入稳定钝态。

Based on the Peterson type formula and the Topper type formula, two formule of effective stress concentration factor are developed.

本文考虑了材料、受载形式、尺寸、错位量、焊接残余应力以及焊趾根部短裂纹对错位板节点疲劳强度的影响，在Peterson公式和Topper公式的基础上，分别建立了两个估算这类节点疲劳强度的有效应力集中系数的公式。

Finally, for actually finite FGM components, the optimization of the compositional gradient of constitutes is helpful to improving the fractural behavior of FGM components.

对于有限体裂纹问题，通过数值求解应力强度因子可知，对功能梯度材料组分梯度进行合理优化，有助于改善功能梯度材料的抗断裂性能。

All in all, under the factors above, the depleted zone in pearlite steel would crack fragilely for formation of creep-flaw in low stress during operating at high temperature before designed expiration date.

异种钢的焊接接头在高温运行中，在高温和应力的作用下，珠光体的脱碳层会产生蠕变裂纹，发生低应力脆性断裂，从而导致接头的早期失效。

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。