THE FRACTURE MECHANISM OF 475°C EMBRITTLEMENT IN A DUPLEX STAINLESS STEEL

The mechanism of “475°C embrittlement” of a duplex stainless steel was investigated using finite element modelling of the stress distribution at brittle fracture initiation. Brittle fracture initiated at a critical shear stress, which increased with ferrite hardness. The fracture stress was affected by the duplex microstructure. Fracture was nucleated by deformation twins, which were identified using electron back-scatter diffraction. The ductile-to-brittle fracture transition was sensitive to age-hardening and could be described simply by the effect of age-hardening and test temperature on the yield stress.     

On basic definitions of unified fracture mechanics terminology

The adoption of unified fracture mechanics terminology (UFMT) will promote efficient communication between specialists in different fields of fracture research, harmonization of national and international standards relating to fracture mechanics, and last but not least improvement of the existing methodology for teaching and education in fatigue and fracture. In this paper the definitions of some basic and related terms included in different standards on fracture mechanics terminology are confronted with one another. Alternative definitions of the same terms are offered. By this strategy the author tries to show that the definitions of basic and related terms appropriate for the UFMT should emerge as a consequence of harmonizing a crack model with an actual crack and then both taken together with a fracture model, laboratory test methods, and failure assessment codes.Published in Problemy Prochonsti, No. 1, pp. 17–29, January, 1996.This paper is published as a matter of discussion.     

区熔单晶硅生产操作指导专家系统

本文介绍区熔单晶硅生产操作指导专家系统。首先，系统实现了连续图象的自动变周期、定瞬间采样，并提出一种新的区域扩张增量图象处理算法．其次，叙述了知识的获取过程及类规则，提出分布的多库结构，并实现了不确定性推理．最后，开发了区熔单晶硅生产操作指导专家系统，实现了从数据和图象采集、处理、事实获取、推理到给出操作指导一体化。     

各国核电厂场外应急计划的比较

本文分析和比较了各国核电厂的应急计划,特别是场外应急的干予水平和应急计划区,讨论了我国干予水平、核电厂应急计划区和香港核应急计划几个实际问题。     

Influence of the Preheat Treatment on the Microstructure and Properties of X37CrMoV5-1 Steel

The technological properties of the hot-work tool steels depend on their microstructural quality induced by the production process and the heat treatment. One of the frequently applied methods to improve microstructure is preheat treatment. The treatment of carbonitriding X37CrMoV5-1 steel has been investigated in fluidized bed furnaces. Thickness and phase composition have been conducted using optical microscopy Neophot 32 and scanning microscopy, JEOL 5400, after etching in nital.     

离心式高炉鼓风机扩压叶片断裂事故分析及处理

通过高炉鼓风机扩压叶片断裂事故，从化学分析、物理检验，结合使用情况对扩压叶片断裂原因进行了详细分析，并提出了改进措施。     

Microscale and mesoscale discrete models for dynamic fracture of structures built of brittle material

In this work we present the discrete models for dynamic fracture of structures built of brittle materials. The models construction is based on Voronoi cell representation of the heterogeneous structure, with the beam lattice network used to model the cohesive and compressive forces between the neighboring cells. Each lattice component is a geometrically exact shear deformable beam which can describe large rigid body motion and the most salient fracture mechanisms. The latter can be represented through the corresponding form of the beam constitutive equations, which are derived either at microscale with random distribution of material properties or at a mesoscale with average deterministic values. The proposed models are also placed within the framework of dynamics, where special attention is paid to constructing the lattice network mass matrix as well as the corresponding time-stepping schemes. Numerical simulations of compression and bending tests is given to illustrate the models performance.     

Schäden durch kerbinduzierte Schwingbrüche

Failures by notch induced fatigue fractures Notches produce local stress concentrations and promote the formation of fatigue cracks. Characteristic types of notches as a result of design, manufacturing and operation are presented and remedial measures are discussed. Examples demonstrate the effect of different kinds of notches on various components.     

一种可切削玻璃陶瓷的压痕断裂特性

将断裂韧性测试的压痕方法与压痕弯曲方法相结合，独立地分离出了压痕残余应力因子ｘ，使其成为可测参量，并建立了压痕一压痕弯曲的断裂韧性测试方法．将这种方法应用于一种可切削玻璃陶瓷的测试，获得的Ｋ１ｃ值为Ｋ１ｃ＝２．０３ＭＰａ·ｍ１／２，与单边切口法（ＳＥＮＢ）获得的Ｋ１ｃ值有较好的一致性．测得的残余应力因子Ｘ＝０．０９３，符合Ａｎｓｔｉｓ经验公式的预测．