常正凯
,
肖金泉
,
陈育秋
,
刘山川
,
宫骏
,
孙超
金属学报
doi:10.3724/SP.J.1037.2012.00056
研究了电弧离子镀磁性靶材使用过程中发生“跑弧”并导致靶材无法稳定刻蚀的问题. 利用有限元方法(FEM)对外加磁场下非磁性靶材系统和磁性靶材系统中的磁场分布进行了模拟. 研究了外磁场对电弧斑点运动的影响机理, 并结合电弧斑点放电的物理机制, 探讨了磁性靶材与低饱和蒸气压金属靶壳、绝缘陶瓷靶壳或软磁性金属靶壳组成复合结构靶材解决磁性靶材使用问题的可行性. 结果表明, 这3种复合结构靶材设计方案均能有效解决电弧离子镀磁性靶材“跑弧”问题. 通过实验得到, 在低饱和蒸气压金属或绝缘陶瓷靶壳设计方案里, 靶材频繁引弧到弧斑能受控运动的转变温度为(136.6±23.0) ℃.
关键词:
电弧离子镀
,
magnetic material
,
finite element method
,
magnetic field distribution
,
composited sructure target
张洪伟张以都吴琼
金属学报
运用大型有限元软件LS-DYNA建立了喷丸强化处理过程的三维有限元模型, 研究了弹丸冲击作用下, 铝合金材料Al 2024-T3动态响应过程中的应力波结构、应变率效应及应力波衰减效应等动态参量; 研究了弹丸搭接率对于残余应力场的影响, 建立了高覆盖率多丸粒强化模型; 研究了冲击顺序、材料应变率及初始残余应力对强化效应的影响; 研究了喷丸强化后的表面微观变形特征. 分析结果表明, 弹丸高速冲击引起的弹塑性双波会在材料内部形成高应变率效应; 弹丸搭接率ζ对于强化效应有明显影响, ζ=1/2是近似的临界值; 不同冲击顺序对于强化效果的影响较小, 材料应变率对于强化效果有显著影响; 初始残余应力对于喷丸强化最终形成的残余应力场的影响取决于弹丸冲击速度; 经过喷丸强化处理, 零件表面形成微米级凹坑, 并且随着冲击次数和喷丸覆盖率的提高, 凹坑深度逐渐增加.
关键词:
喷丸
,
finite element method
,
residual stress
,
impact
,
strain rate
,
coverage ratio
张昭
,
刘亚丽
,
张洪武
金属学报
采用完全热力耦合模型分析轴向载荷变化对搅拌摩擦焊接过程的影响, 发现较低的轴向载荷会导致搅拌摩擦焊接无法完成. 搅拌摩擦焊接构件上表面材料由于受到搅拌针和肩台旋转的作用, 导致上表面材料变形程度较下表面高, 材料沿焊缝中心线的变形并非严格对称, 前进侧材料的变形程度较后退侧高, 搅拌头轴向载荷的增加会减弱这种不对称性. 搅拌摩擦焊接过程中的最高温度随轴向载荷的增加而增加,且搅拌头轴向载荷的增加会促使搅拌区附近的温度分布趋于均匀.
关键词:
搅拌摩擦焊接
,
fully coupled thermo-mechanical model
,
finite element method
李晓军
,
柴东朗
,
郗雨林
金属学报
= [刊，中]///金属学报.¾2004,40(9).¾ 927~929
采用有限元方法仿真模拟了SiC颗粒(SiCp)增强镁基复合材料中实际形状的增强体周围的微区应力场. 结果表明, 不同形状的增强体颗粒附近的微区应力场差异很大, 个别颗粒会在低应力下失效. 当增强体的体积分数较少时, 每个增强体的微区应力场受其它增强体影响不大, 近似给出单个增强体的形状就可以仿真模拟增强体附近的微区应力场. 利用粉末冶金法制备了颗粒增强镁基复合材料, 观察其拉伸断口, 并利用有限元方法进行
关键词:
镁基复合材料
,
finite element method
,
analog
simulation
K. B. Nielsen
,
M. R. Jensen and J. Danckert Department of Production
,
Aalborg University
,
Denmark
金属学报(英文版)
The paper focuses on the combination of the Finite Element simulation and optimization to improve process or product quality. Three different examples to illustrate the developed genetic approach are given. In all three examples is-DYNA3D is used to simulate the process and a general aptimiza- tion sensitivity based strategy is utilized to improve the design. The included examples are: 1) stretch bending of tubes, 2) bulging of tubes, and finally 3) hydromechanical deep drawing. these examples clearly illustrate the potential of systematic optimization in the area of metal processing.
关键词:
finite element method
,
null
,
null
,
null
,
null
J.C. Li
,
B.F. Wang
,
J.Z. Cui
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
金属学报(英文版)
With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density in the aluminum melt and magnetic field interaction of four coils applied with same currents were investigated. Calculating results showed that magnetic flux density in the aluminum melt was greatly improved and the magnetic field interaction among different coils was decreased when external part of mould is made of soft magnetic material. Based on the finding, a four-strand low-frequency electromagnetic casting 6063 aluminum alloy experiment was carried out in the laboratory. The experiment showed that the surface of the billet was smooth and had no exudations and cold shuts, the as-cast microstructures were fine, uniform, equiaxed, net-globular or globular under low-frequency electromagnetic field. The microstructure becomes finer with increased current value.
关键词:
low-frequency electromagnetic casting
,
null
