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EFFECT OF PARAMETERS ON DENDRITIC PATTERNS AND MICROSEGREGATION OF Ni-Cu BINARY ALLOY

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EFFECT OF PARAMETERS ON DENDRITIC PATTERNS AND MICROSEGREGAT...

第五届国际材料与热加工物理模拟及数值模拟学术会议

作者： Changsheng ZHU1,2, Li FENG1, Zhiping WANG1,Rongzhen XIAO1 1 state key lab.ratory of gansu {4. non-ferrous Metal materials, lanzhou university of technology lanzhou, 730050, china 2 CAD Center, lanzhou university of technology lanzhou, 730050, china

The effects of various material parameters such as solid diffusivity Ds, anisotropy parameterε , interface kinetic coefficient β and surface energy σ on dendritic patterns and microsegregation is investigated by using a phase-field model which couples concentration gradient for two-dimensional simulation of binary alloy solidification. The computed results indicate that, different material parameters lead to different dendritic patterns and severity of microsegregation. The smaller Ds is, as well as the larger ε, β, σ are, the greater the dendritic tip velocity is, the more developed the side-branches are. The larger Ds is, the less drastically the solid’s solute composition undulates, and the extent of microsegregation minishes;ε affects the dendritic tip’s steady state, the larger εis, the more drastically the solid solute composition’s undulation is, and the severity of microsegregation ahead of solid/liquid interface aggravates;the larger β is, the more acutely the solid solute composition’s fluctuates, but the severity of microsegregation ahead of solid/liquid interface reduces;On increasing σ , the fluctuant extent of the solid’s solute composition reduces correspondingly, and an increased level of σ alleviates the severity of microsegregation ahead of solid/liquid interface.

关键词： Phase-field model Dendritic patterns Microsegregation Numerical simulation

Research of Tribological Behaviors of a New Aluminum Bronze

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Research of Tribological Behaviors of a New Aluminum Bronze

14.(th) Congress of International Federation for Heat Treament and Surface Engineering

作者： XU Jian-lin, WANG Zhi-ping, CHEN Chao1. state key lab.of gansu New {4.-ferrous Metal materials, lanzhou university of Science and technology, lanzhou, china 2. College of Mechanic-Electronic Engineering, lanzhou university of Science and technology, lanzhou, china

＜正＞ The tribological behaviors were investigated in a new high strength and wear resistant aluminum bronze, with its friction coefficient and wear-rate lower than those of ZQA19-4.and ZQA110-4.4.alloys in terms of Chinese national standard. The results showed that different tribological behaviors were attributed material itself. Under boundary lubrication condition, major wear mechanisms of aluminum bronze are adhesive wear and attrition wear. Its wearability depends mainly on material microstructure, shedding hard-particles, rakes and small pits that can store lubricant. The new aluminum bronze may find wide application in high sliding speed, heavy load and boundary lubrication condition.

关键词： aluminum bronze tribological behaviors

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单旁路耦合电弧GMAW高速焊接工艺

上海交通大学学报 2010年第S1期44卷 50-53页

作者：石玗薛诚钟浩樊丁兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室兰州730050 兰州理工大学有色金属合金及加工教育部重点实验室兰州730050

介绍了单旁路耦合电弧熔化极气体保护电弧焊(DE-GMAW)方法的原理和系统组成,由于旁路电弧的分流作用使得电弧压力和母材热输入显著降低,从而有利于高速焊接过程.通过实验对比了单旁路耦合电弧和传统GMAW方法在高速焊接时的效果.结果表明... 详细信息

介绍了单旁路耦合电弧熔化极气体保护电弧焊(DE-GMAW)方法的原理和系统组成,由于旁路电弧的分流作用使得电弧压力和母材热输入显著降低,从而有利于高速焊接过程.通过实验对比了单旁路耦合电弧和传统GMAW方法在高速焊接时的效果.结果表明:两者在焊接总电流相同的条件下,单旁路耦合电弧GMAW方法能获得更高的焊接速度和良好的焊缝成形.

关键词：单旁路耦合电弧熔化极气体保护电弧焊高速焊接

Monitoring of Pulsed MIG Welding Process of Aluminum Alloy Based on the lab.IEW Real-time Vision

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Monitoring of Pulsed MIG Welding Process of Aluminum Alloy B...

第三十届中国控制会议

作者： HUANG Jiankang~1,LU Lihui~2,SHAO Ling~2,SHI Yu~1,FAN Ding~1 1.key lab.ratory of non-ferrous Metal Alloys and Processing under the management for Ministry of Education,{4. university of technology,{4. 730050,P.R.china 2.state key lab.ratory of gansu {14. non-ferrous Metal materials,{4. university of technology,{4. 730050,P.R.china

＜正＞A real-time synchronous acquisition and control system was designed to meet the requirements of measurement and control for pulsed MIG welding process of aluminum alloy using virtual instrument design software lab.*** the characteristics of pulsed MIG welding,development efficiency and control response time,the mode of "data acquisition card+ PC+real-time controller" was adopted and the parallel processing of voltage,current and vision signals was realized with complex signal processing algorithm based on hardware platform and COM *** test results show that the developed platform can acquire and process the information real-timely and effectively in pulsed MIG welding process of aluminum alloy and also has friendly program interface and good expansibility.

关键词： lab.VIEW Pulsed MIG welding Real-time visual processing COM technology

The Application of Surface Modification in Controlling Aggregation of Nano-Powder Particles

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The Application of Surface Modification in Controlling Aggre...

第八届国际粉体检测与控制学术会议

作者： Xu Jianlin~(1,2),Zhang Lihui~(1,2),Yang Shuhua~(1,2),Long Dawei~(1,2),Chen Jidong~(1,2) 1.state key lab.ratory of gansu {4. non-ferrous Metal materials, lanzhou university of technology,lanzhou,730050 china 2.key lab.ratory of non-ferrous Metal Alloys and Processing,The Ministry of Education, lanzhou university of technology,lanzhou,730050 china No.287,Langongping Road,Qilihe District,lanzhou,730050 china

Nano-powder materials exhibit some novel properties and hence,are aroused general *** preparation technology is more important in preparation nano-powder *** at incident aggregation phenomenon of nanopowder particles,surface modification technology is an effective method in controlling aggregation of nano-powder particles. In the paper,the fundamentals and applied ranges of some surface modification technology are introduced,including thermal decomposition-reduction method,chemical plating,homogeneous precipitation method,sol-gel method,surfaceactive agent method,mcroemulsing method,coupling agent method,esterifying reaction method and surface boundbranch *** surface modification methods in controlling aggregation and ensuring properties of nano-powder particles have some advantages.

关键词： Nano-powder particles Surface modification Aggregation

异质体材料微结构力学响应计算与虚拟失效行为

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系统仿真学报 2009年第16期21卷 4966-4970页

作者：任淮辉李旭东李俊琛甘肃省有色金属新材料省部共建国家重点实验室兰州理工大学兰州730050

通过微观组织结构的模块化与可视化设计,可以实现对多元多相异质体材料微结构组成物的几何形状、尺寸大小、空间位置分布、增强(韧)相的体积份额以及取向分布等按照设计要求进行任意调整与组合,从而构造出一系列复杂的、多种多样的材料... 详细信息

通过微观组织结构的模块化与可视化设计,可以实现对多元多相异质体材料微结构组成物的几何形状、尺寸大小、空间位置分布、增强(韧)相的体积份额以及取向分布等按照设计要求进行任意调整与组合,从而构造出一系列复杂的、多种多样的材料微观组织结构。在此基础上,利用有限元法对异质体材料微结构进行细观力学响应的数值计算,对于识别"材料结构弱点",评估微裂纹的启裂、扩展,预测异质体材料微结构材料损伤后的材料性能,推演"微结构虚拟失效"行为具有重要的意义。

关键词：材料微结构数值模拟材料结构弱点虚拟失效各向异性

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杯形件反挤压变形力的滑移线场数值分析解

山东大学学报（工学版） 2011年第6期41卷 66-69页

作者：秦小琼刘德学兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室甘肃兰州730050 兰州理工大学机电工程学院甘肃兰州730050

因工程设计中挤压力的计算依赖于经验公式,误差较大且不利于优化设计,基于经典塑性理论,运用数学方法探索更准确方便的挤压力的求解模型。以滑移线场为理论平台,以杯形件反挤压过程为研究对象,分析不同压缩比的系列滑移线特征并叠加得... 详细信息

因工程设计中挤压力的计算依赖于经验公式,误差较大且不利于优化设计,基于经典塑性理论,运用数学方法探索更准确方便的挤压力的求解模型。以滑移线场为理论平台,以杯形件反挤压过程为研究对象,分析不同压缩比的系列滑移线特征并叠加得到代表滑移线场。在求解应力场及变形力的基础上,通过曲线拟合方法研究滑移线场参数与模具几何参数的解析关系,从而建立变形物理参数与几何参数的数值分析模型。该数值分析模型所得解析解比滑移线场数值解具有更明显的物理意义,在知道变形几何参数的前提下,可方便求解挤压力。最后通过实测挤压力、并结合经验公式进行验证。结果表明数值分析模型计算结果较准确,并可作为目标函数实现工艺优化设计。

关键词：挤压力滑移线数值分析

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溶质梯度影响非等温凝固过程的相场法模拟

系统仿真学报 2009年第10期21卷 3088-3091页

作者：朱昌盛杨世银王智平肖荣振兰州理工大学CAD中心兰州730050 兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室兰州730050

采用相场法模拟了Ni-Cu二元合金非等温凝固过程溶质梯度对枝晶生长的影响。结果表明:非等温凝固时,潜热的释放使固相区的温度比液相中的高,在二次枝晶生长较为密集的中心区域温度最高,固相区温度升高会使得金属重熔,发生重熔现象,晶体... 详细信息

采用相场法模拟了Ni-Cu二元合金非等温凝固过程溶质梯度对枝晶生长的影响。结果表明:非等温凝固时,潜热的释放使固相区的温度比液相中的高,在二次枝晶生长较为密集的中心区域温度最高,固相区温度升高会使得金属重熔,发生重熔现象,晶体的生长速度和凝固区域的温度随之出现波动。溶质梯度对溶质分布影响较大,溶质梯度增加,固相率提高,溶质分配系数k增大,固相区溶质富集,形成了过饱和的固相,溶质截流效应明显。

关键词：相场法非等温凝固溶质梯度溶质截流

Effects of deformation parameters on microstructure and mechanical properties of magnesium alloy AZ31B

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Rare Metals 2006年第z2期25卷 105-110页

作者： ZHANG Shaoming YANG Bicheng XU Jun SHI Likai CHEN Guoliang state key lab.ratory for advanced Metals and {4. University of Science and Technology Beijing Beijing 100083 China General Research Institute for non-ferrous Metals Beijing 100088 China General Research Institute for Non-Ferrous Metals Beijing 100088 China General Research Institute for Non-Ferrous Metals Beijing 100088 China General Research Institute for Non-Ferrous Metals Beijing 100088 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Plastic deformation and dynamic recrystallization (DRX) behaviors of magnesium alloy AZ31B during thermal compression and extrusion processes were studied. In addition, effects of deformation temperature and rates on the microstructure and mechanical properties were investigated. The results show that the DRX grains nucleate initially at the primary grain boundaries and the twin boundaries, and the twinning plays an important role in the grain refinement. The DRX grain size depends on the deformation temperature and strain rate The average grain size is only 1 μm when the strain rate is 5 s-1 and temperature is 250 ℃. It is also found that the DRX grain can grow up quickly at the elevated temperature. The microstructure of extruded rods was consisted of tiny equal-axis DRX grains and some elongated grains. The rods extruded slowly have tiny grains and exhibit good mechanical properties.

关键词： magnesium alloy thermal simulation extrusion dynamic recystallization