增塑型超韧尼龙11的力学性能和增塑机理

增塑后尼龙１１的冲击强度及断裂伸长率大幅提高,但断裂强度并未大幅降低。尼龙１１的增塑机理是,增塑剂破坏了尼龙１１的分子间氢键作用。研究表明,增塑型超韧尼龙１１的断裂面具有独特的形态,这是一种首次发现的新型断裂现象。本文首次将上述现象归结为“多重裂延”机理。     

GCr15钢的韧化处理

根据不均匀奥氏体加热淬火原理，通过加热过程控制，使ＧＣｒ１５钢淬火后既细化了奥氏体晶粒又细化了马氏体，同时还获得了低碳板条马氏体及呈薄状或集聚态的残余奥氏体包围在碳化物周围的组织，该方法是韧化ＧＣｒ１５钢的有效途径。     

用活性端基聚乙二醇对高交联度不饱和聚酯的增韧改性研究:Ⅱ结构与性能

用合成的含有反应活性端基的聚乙二醇改性不饱和聚酯交联网络,研究结果表明,含有反应性马来酸端基的聚乙二醇参与了不饱和聚酯的固化反应,在交联网络中构成不同长度的柔性链段,显著地提高了不饱和聚酯的韧性,而其它力学性能得以保持。通过动态力学研究网络的结构特征,将其应用于模压塑料的增韧获得了满意的效果。     

Toughening due to domain switching in single crystal ferroelectric materials

In this paper Mode I steady state crack growth in single crystal ferroelectric materials is investigated. Specifically, the fracture toughness enhancement due to domain switching near a steadily growing crack tip is analyzed. For this purpose, an incremental phenomenological constitutive law for single crystal ferroelectric materials is implemented within a finite element model to calculate the stress and remanent strain fields around the crack tip. Also, the ratio of the far field applied energy release rate to the crack tip energy release rate, i.e. the toughening, is calculated. The numerical computations are carried out for single crystal ferroelectric materials of tetragonal or rhombohedral structure with different switching hardening and irreversible remanent strain levels. Toughening levels for crack growth along different crystallographic directions and planes are obtained and compared. Results from numerical computations for the toughening anisotropy for both tetragonal and rhombohedral crystals are presented and discussed.     

AA1100铝箔的强韧化

采用光学显微镜、透射电镜和力学性能实验机等设备 ,研究了均匀化和成品工艺因素对AA1 1 0 0铝箔强韧性的影响。结果表明 ,材料经 560℃ ,1 6h均匀化处理和 2 30～ 2 60℃ ,1h退火处理后 ,σb≥ 1 2 0MPa ,δ≥2 0 % ,达到最佳的强韧化效果。同时对该材料的强韧化机理进行了探讨。     

20Cr1Mo1V1钢的分级时效工艺研究

研究了 2 0Cr1Mo1V1钢的强韧化工艺。所优化出的分级时效工艺能使其强度和韧性达到质保书的要求。     

PVC纳米复合材料增强和增韧研究进展

通用塑料的高性能化和多功能化是开发新型材料的一个重要趋势,而将纳米粒子作为填料来填充改性聚合物,是获得高强高韧复合材料有效方法之一。文中对近年来纳米增韧PVC的制备方法,增韧机理和发展趋势作了进行了说明。     

液晶共聚酯酰胺对PET／PA66的原位增容,增强,增韧作用

研究了液晶共聚酯酰胺ＬＣ３０对聚树苯二甲酸乙二酯／聚酰胺６６共混物的原侠增容，增强，增韧作用。结果表明，ＬＣ３０有效地改善了ＰＥＴ／ＰＡ６６共混物的形态结构，对ＰＥＴ／ＰＡ６６共混物起到了明显的增容作用。     

MoSi2金属间化合物复合材料的强韧化机理及其制备技术

重点介绍了国际上MoSi2 复合材料的热压、热等静压 (HIP)、机械合金化 (MA)、反应烧结等有效制备技术。文章指出MoSi2 的复合化及其复合技术是改善其室温塑性及高温强度的有效途径。MoSi2 复合材料的晶须增强是以裂纹反射为其主要机理 ,而颗粒强韧化是由于第二相的晶界钉扎作用。文章最后指出 ,建立相成分与性能的对应关系有助于工艺优化及其系统性研究     

Cavitation Instabilities in Plastics and Rubber-Modified Plastics

Spherical void expansion in plastics and rubber-modified plastics is investigated under radial traction conditions. The plastics are modeled as elastic-plastic pressure-sensitive materials and the rubbers are modeled as nonlinearly elastic materials. First, the growth of a spherical void in an infinite plastic matrix is investigated under remote radial traction conditions. The results show that the cavitation stress of the plastic decreases significantly as the pressure sensitivity increases. Then, the growth of a spherical void located at the center of a spherical rubber particle in an infinite plastic matrix is investigated under remote radial traction conditions. The results indicate that without any failure criteria for the rubber, the cavitation stress does not exist when the void is small and the rubber is characterized by high-order strain energy functions. However, when a failure criterion for the rubber is considered at a finite stretch ratio, the results show that the cavitation stress for the plastic with the rubber particle becomes close to that for the plastic without the rubber particle. This revised version was published online in August 2006 with corrections to the Cover Date.