J. Wang
,
J. Chen
,
Z. Zhao
,
X.Y. Ruan
金属学报(英文版)
The microstructural evolution of microalloyed steel during hot forging process was investigated using physical simulation experiments. The dynamic recrystallized fraction was described by modifying Avrami's equation, the parameters of which were determined by single hit compression tests. Double hit compression tests were performed to model the equation describing the static recrystallized fraction, and the obtained predicted values were in good agreement with the measured values. Austenitic grain growth was modeled as: Dinc5 = D05 + 1.6 × 1032 t·exp () using isothermal tests. Furthermore, an equation describing the dynamic recrystallized grain size was given as Ddyn = 3771·Z-0.2. The models of microstructural evolution could be applied to the numerical simulation of hot forging.
关键词:
microalloyed forging steel
,
再结晶
,
晶粒长大
H. Tian
,
J. Wang
,
W.P. Dong
,
J. Chen
,
Z. Zhao
,
G.M. Wu
金属学报(英文版)
Traditionally a rotary forging process is a kind of metal forming method where a conic upper die, whose axis is deviated an angle from the axis of machine, forges a billet continuously and partially to finish the whole deformation. For the rotary forging process simulation, more researches were focused on simulating the simple stage forming process with axisymmetric part geometry. Whereas in this paper, the upper die is not cone-shaped, and the billet is non-axisymmetric. So the movement of the punch is much more complicated than ever. The 3D FEM simulation models for the preforming & final forming processes are set up after carefully studying the complicated movement pattern. Deform-3D is used to simulate the material flow, and the boundary nodal resisting forces calculated by the final stage process simulation is used to analyze the final forming die strength. The CAE analysis of the die shows that the design of the final forming die is not reasonable with lower pre-stress which is easy to crack at the critical corners. An optimum die design is also provided with higher pre-stress, and verified by CAE analysis.
关键词:
numerical simulation
,
null
,
null
王晓旭
,
陈利
材料工程
doi:10.3969/j.issn.1001-4381.2011.11.001
通过单根Z-pin从复合材料层合板中拔出的试验方法,测试了Z-pin的拔出强度,计算了Z-pin的临界埋入深度,并引入抗拉强度利用率概念来表征Z-pin的抗拉强度在拔出过程中的利用程度.结果表明,直径0.50mm和0.28mm的Z-pin临界埋入深度分别约为5.1mm和3.1mm.当Z-pin的埋入深度小于临界埋入深度时,Z-pin从层板中拔出；Z-pin拔出强度与埋入深度成正比,与Z-pin的直径成反比；当Z-pin的埋入深度大于临界埋入深度时,Z-pin发生断裂,Z-pin的抗拉强度利用率达到100％.最后提出了提高抗拉强度利用率的建议.
关键词:
Z-pin
,
拔出强度
,
复合材料
,
拔出试验
,
抗拉强度
王晓旭
,
陈利
航空材料学报
doi:10.3969/j.issn.1005-5053.2011.4.017
通过三种复合材料Z-pin的轴向压缩试验,观察了各Z-pin的压缩行为,分析了三种复合材料Z-pin在不同长度时的极限应力及其失效形式.结果表明,直径为0.50mm的碳纤维Z-pin的压缩性能最好,其各长度Z-pin所能承担的极限应力都较大.直径0.28mm的碳纤维Z-pin易发生失稳现象,芳纶纤维Z-pin在压缩力的作用下,接触端容易受到破坏.两种碳纤维Z-pin临界应力的理论值与试验值吻合较好,但芳纶纤维Z-pin的临界应力的试验值比理论值偏低.
关键词:
Z-pin
,
复合材料
,
压缩试验
,
临界应力
Li XING
,
Jie ZHAO
,
Fuzhong SHEN
,
Wei FENG
材料科学技术（英文）
A Z-parameter method is used to evaluate the damage process of HK40 austenitic steel. By using Z-parameter based on the Larson-Miller method, the nonlinear master curve of the log stress vs Larson-Miller parameter P can be expressed as: P=27.74-3.4lgσ-0.032σ, and a family of curves parallel to the master curve can be written as: P=(27.74-Z)-3.4lgσ-0.032σ, where Z represents the magnitude of the deviation from the master curve. According to the creep rupture data both from different segments of a serviced tube and from the same segment locations with different service time, the value of parameter Z has close relationship with the deterioration of creep rupture properties. The damage state of the samples is evaluated by monitoring the changes in natural frequency f and Young0s modulus E, and the relationships between Z and the damage parameters are discussed.
关键词:
Damage evaluation
,
蠕变断裂
,
奥氏体钢
,
Z参数
詹勇军
,
王锋
,
白黎
,
张素银
,
唐永健
,
吴卫东
,
谌家军
材料导报
以材料非线性光学性质的测试为基础,介绍了原始Z扫描技术的基本原理与数据处理;重点论述了双色时间分辨Z扫描技术的理论,并分析了它在材料光学非线性效应测试中展现的优越性以及应该注意的关键问题.根据Z扫描技术理论和实验的最新研究成果,总结了Z扫描技术的两条发展思路,即:CCD相机代替能量或功率计进行信号的采集和多种改进方法应用于实验测试.
关键词:
Z扫描技术
,
非线性光学效应
,
双色时间分辨Z扫描技术
,
CCD相机
李伟东
,
刘刚
,
安学锋
,
益小苏
复合材料学报
研究了层间“离位”附载多孔薄膜结构形式增韧层的大厚度纤维预成型体中等代流体(树脂)沿预成型体厚度方向(z向)的流动行为,通过压力传感器监测z向流动RTM(z-RTM)工艺注射过程中进、出胶口压力的变化规律,进一步反推树脂在层间“离位”增韧与非增韧预成型体中的宏观流动及微观浸润模式.结果表明,在z-RTM工艺注射过程中,树脂在沿纤维束间z向快速流动的同时完成对纤维丝束内部的浸润.层间“离位”附载的增韧层虽延缓了树脂的宏观流动,但使流动前锋曲面更加平滑.层间“离位”增韧预成型体z向渗透率为3.5×10-15m2,与非增韧预成型体的z向渗透率2.9×10-14m2相比,降低约一个数量级.
关键词:
z向流动
,
树脂传递模塑
,
预成型体
,
“离位”增韧
,
渗透率
朱书成
钢铁研究学报
采用高倍金相检验、扫描电镜及能谱分析等方法对120mm Q390GJC-Z35特厚板的z向性能不合缺陷进行了研究。结果表明：z向性能不合主要是由于钢锭存在着较严重的中心偏析,在不合试样断口处存在着较多的块状（Nb、Ti）C聚集,块状的（Nb、Ti）C成为裂纹源。此外,偏析处还存在贝氏体等硬相组织,更加剧了断裂扩展,导致z向性能不合。通过优化成分设计,加强精炼过程控制,改进模铸浇注工艺,制定合理热处理工艺等相关措施,取得了良好的效果。
关键词:
Q390GJC-Z35
,
z向性能
,
不合
,
原因分析
,
措施
