TRIZ研究及其在定向凝固设备设计中的应用

TRIZ是对大量的专利发明进行研究后,形成的解决工程问题的方法论.介绍了TRIZ的起源、基本理论及产品创新的一般过程,并通过其在特殊定向凝固设备设计中的应用详细论述了TRIZ解决问题的基本步骤.     

Morphological evolution model for unidirectional solidification of multicomponent alloys

Based on the nonlinear interaction of the different species and the calculation of phase diagram, a self-consistent model is developed to describe the interface morphology evolution during unidirectional solidification of multicomponent alloys. This model takes full account of the mutually coupled effect of temperature field, solute field, interface energy and interface attachment kinetics. In comparison with linearization analysis of multicomponent, it not only extends the convergent range of the analysis, but also greatly improves the applicability.     

Fabrication of pure copper rods containing continuous columnar crystals by continuous unidirectional solidification technology

Pure copper rods containing continuous colunmar crystals were fabricated using the downward CUS (Continuous Unidirectional Solidification) equipment. When the technological parameters were set as the ranges of mould temperature 1100-1300℃, cooling distance (the distance from the exit of the cast mould to the start point of cooling) 10-20 nun, casting speed 0.2-2.5 mm/s, cooling water (20-25℃) volume 1000-1320 L/h, and when these parameters matched reasonably, the CUS process was performed stably, and pure copper rods containing continuous columnar crystals with bright and smooth surface were produced. The dendritic arm spacing of the crystals in copper rods decreased with increasing the casting speed. The results of the texture by X-ray diffraction analysis showed that the rods has strong (100) fiber texture.     

基于元胞自动机法的晶粒长大模拟

采用元胞自动机(Cellular Automata,简称CA)法对晶粒长大过程进行了计算机模拟和分析.模拟结果表明,CA法能够较好地模拟晶粒长大过程,所反映的晶界迁移规律及其拓扑特征符合晶粒长大的物理机制,是一种简便、有效的模拟方法.     

基于元胞自动机法的晶粒长大模拟

采用元胞自动机（Cellular Automata，简称CA）法对晶粒长大过程进行了计算机模拟和分析．模拟结果表明，CA法能够较好地模拟晶粒长大过程，所反映的晶界迁移规律及其拓扑特征符合晶粒长大的物理机制，是一种简便、有效的模拟方法．     

Macrostructure and properties of thin walled copper tubes prepared by the downward continuous unidirectional solidification method

The macrostructure and properties of the thin walled copper tube prepared by the downward continuous unidirectional solidification (DCUS) method were studied.The result shows that the macrostructure is closely related to the solid-liquid interface profile,which is influenced by the distance between the cooling water location and the solidification front.The mechanical properties of the thin walled copper tube prepared by the DCUS method are near those of the normal cast copper,and it has good relative densi...     

高温合金铸件凝固过程模拟的CA-FE法

运用现代造型软件PRO/E和有限元分析软件ANSYS,并且利用MATLAB软件的计算功能和图形功能,实现了对复杂高温合金铸件凝固过程的温度场和微观组织的仿真;同时耦合了铸件凝固过程模拟的微观动力学模型和宏观温度场模型,建立起实用高效的CA-FE集成模拟法。运用该模拟法研究某航天发动机高温合金铸件,得到其凝固过程的温度场及其微观晶粒组织,模拟结果和实际符合较好。     

Cellular automata modelling of grain coarsening during reheating——Ⅱ. Abnormal grain growth

The 2-dimensional cellular automata (CA) simulation technique has been utilized to investigate the abnormal grain coarsening. The growth of abnormal grains is modelled under this assumption that different grains have different boundary energies and boundary mobilities. As temperature increases, some grains may first get rid of the particle pinning effect. Thus a high probability is obtained for atoms to jump over the boundary, so that they can consume other primary retained grains quickly. From the simulation,the characteristics of the abnormal grain coarsening under different conditions are demonstrated successfully. An experiment has also been carried out to reflect the abnormal grain coarsening on the microalloy steel. Simulation results are quite close to the experimental evidence.     

铸件凝固组织微观模拟的研究进展

综述了铸件凝固过程微观组织模拟的研究进展，详细介绍了确定性方法、随机性方法、相场方法的发展过程．论述了共晶合金和枝晶合金凝固组织的数值模拟进展．最后，预测了凝固组织数值模拟研究的未来发展方向。     

Computational algorithms for simulating the grain structure formed on steel billets using cellular automaton and chaos theories

The development of some computational algorithms based on cellular automaton was described to simulate the structures formed during the solidification of steel products.The algorithms described take results from the steel thermal behavior and heat removal previously calculated using a simulator developed by present authors in a previous work.Stored time is used for displaying the steel transition from liquid to mushy and solid.And it is also used to command computational subroutines that reproduce nucleatio...     

计算机模拟晶粒的正常生长过程

通过Delphi软件的图象操作语言对各晶粒进行着色,以蒙特卡罗(Monte Carlo)模型为依据,直观地表现出晶粒生长各阶段的情况.计算结果表明,其生长情况与生长动力学相符合;生长过程中的几何拓扑变化明显.     

Size distributions and magic number characteristics of cluster configurations formed during solidification processes of liquid metal Al

Recently, the studies on the stability and magic number characteristics of cluster con- figurations, especially of larger cluster configurations, have become a very active area in physics, chemistry and materials science[1―8]. However, at present, the experimental stud- ies are mainly carried out on fine powder obtained by means of physical or chemicalmethods (such as ionic spray, laser evaporation, air-actuated technology, gas discharging, and organic metal chemical reaction) [1-5], and the t…     

铝硅合金凝固组织的数值模拟

通过热焓法处理结晶潜热的二维不稳定热传导方程模拟凝固温度场，利用Scheil模型模拟质量浓度场，提出了枝晶尖端生长动力学修改模型，在温度场模拟与质量浓度场模拟基础上模拟了凝固过程中铝硅合金的组织在计算机上实现了组织形成过程的可视化，模拟结果与实验结果进行比较，两者基本吻合。     

Q345钢凝固组织的模拟计算

运用ProCAST软件对Q345钢凝固过程进行数值模拟.铸坯中心等轴晶率模拟结果与工业试验用钢检测结果相一致,同时应用CAFE机理研究了过热度对Q345钢铸坯凝固组织的影响及规律。结果表明,过热度对凝固组织结构影响较大,晶粒平均半径由75℃的0.231 mm降低到15℃的0.191 mm。因此,实际生产过程中,在保证钢液顺利浇注的情况下,综合考虑铸坯质量与生产顺利,过热度需控制在15℃左右为宜。     

Nature of large （Ti, Nb）（C, N） particles precipitated during the solidification of Ti, Nb HSLA steel

To investigate the microsegregation phenomena and complex （Ti, Nb）（C, N） precipitation behavior during continuous casting, a unidirectional solidification unit was employed to simulate the solidification process. The samples of Ti, Nb-addition steels after unidirectional solidification were examined using field emission scanning electron microscope （FE-SEM） and electron probe X-ray microanalyzer （EPMA）. In such specimens, dendrite structure and mushy zone can be detected along the solidification direction. It shows that the addition of titanium, niobium to high-strength low-alloyed （HSLA） steel results in undesirable （Ti, Nb）（C, N） precipitation because of microsegregation. The effect of cooling rate on （Ti, Nb）（C, N） precipitation was investigated. The composition of large precipitates was determined using FE-SEM with EDS. Large （Ti, Nb）（C, N） precipitates could be divided into three kinds according to the composition and morphology. With the cooling rate increasing, Ti-rich （Ti, Nb）（C, N） precipitates are transformed to Nb-rich （Ti, Nb）（C, N） precipitates.     

凝固过程微观组织数值模拟研究进展

介绍目前几种主要的微观组织模拟方法、确定性方法、随机性方法和相场法及其主要建模思想和优缺点.分析了各方法在凝固过程微观组织模拟方面的国内外研究进展和现状.研究结果表明,多种模型相结合与宏观场模拟相耦合是今后凝固微观组织数值模拟的发展趋势.     

晶粒长大过程微观组织演变Monte Carlo方法模拟

Monte Carlo模拟方法中采用了结点再取向“择优转换原则”，并用线性Turnbull动力学晶界移动速率公式概率形式确定结点取向转换概率，对晶粒长大过程进行长时间的模拟．模拟的组织变化图像与实际材料的正常晶粒长大组织完全一致；长大过程分为不稳定和稳定两个阶段，稳定阶段晶粒长大指数n达到了理论值0．5；在完整的晶粒长大过程中，晶粒尺寸分布并不具有严格的自相似性，系由不稳定长大阶段的对数正态分布（Lognormal）向稳定阶段的伽马（Gamma）分布变化。     

晶粒长大过程微观组织演变Monte Carlo方法模拟

Monte Carlo模拟方法中采用了结点再取向“择优转换原则”,并用线性Turnbull动力学晶界移动速率公式概率形式确定结点取向转换概率,对晶粒长大过程进行长时间的模拟.模拟的组织变化图像与实际材料的正常晶粒长大组织完全一致;长大过程分为不稳定和稳定两个阶段,稳定阶段晶粒长大指数n达到了理论值0.5;在完整的晶粒长大过程中,晶粒尺寸分布并不具有严格的自相似性,系由不稳定长大阶段的对数正态分布(Lognormal)向稳定阶段的伽马(Gamma)分布变化.     

Al-Si合金(A357)重力铸造充型及凝固过程模拟

利用多通道数据采集系统对铸件特定部位的温度进行测量,以掌握该点的凝固和补缩,并利用O lym pu s金相显微镜观察铸件关键部位的宏观组织,进而分析其凝固方式.用商业化模拟软件Z-C ast对铝合金拉伸试棒充型及凝固过程进行模拟,对实际浇注实验中测试点的温度场进行模拟,并将模拟结果与实验结果进行比较.结果表明,当金属铸型的预热温度较低时,必须采用较高的浇注温度才能够使铸型充满,试棒在凝固过程能够得到有效补缩,从而消除了由于糊状凝固造成的显微缩松.铸造模拟软件Z-CA ST能够准确的模拟铝合金铸件充型凝固过程,提供较准确的流场、温度场信息,预测缺陷及其出现位置.