共查询到20条相似文献,搜索用时 15 毫秒
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The high-temperature deformation and failure behavior of an orthorhombic titanium aluminide sheet alloy (fabricated by diffusion
bonding of six thin foils) was established by conducting uniaxial tension and plane-strain compression tests at 980 °C and
strain rates between 10−4 and 10−2 s−1. The stress-strain response was characterized by a peak stress at low strains followed by moderate flow softening. Values
of the strain-rate sensitivity index (m) were between 0.10 and 0.32, and the plastic anisotropy parameter (R) was of the order of 0.6 to 1.0. Cavity nucleation and growth were observed during tensile deformation at strain rates of
10−3 s−1 and higher. However, the combined effects of lowm, low cavity growth rateη, and flow softening were deduced to be the source of failure controlled by necking and flow localization rather than cavitation-induced
fracture prior to necking. 相似文献
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Young-Suk Kim Sung-Yeun Won Kyoung-Hoan Na 《Metallurgical and Materials Transactions A》2003,34(6):1283-1290
Most failures of ductile materials in metal-forming processes occur due to material damage evolution (void nucleation, growth,
and coalescence). The current article examines the modified yield function of Liao et al., in conjunction with Hosford’s yield criterion, to clarify the plastic-deformation characteristic of voided anisotropic sheet
metals. As such, the void growth of an anisotropic sheet under biaxial tensile loading and the damage effect of void growth
on the forming limits of sheet metals are investigated. Plus, the process length defining the neck geometry is included in
the Marciniak and Kuczynski (M-K) model to incorporate the effect of triaxial stress in a necked region on the forming limits.
The predicted forming limits were compared with experimental data, and a satisfactory agreement was obtained. 相似文献
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针对以往热镀锌板以碳作为强化元素的碳锰设计中易出现成品带钢板面不良的缺陷,以及采用超低碳钢添加微合金元素强化时成本较高的问题,以厚度规格为0.3 mm、强度为320 MPa的典型薄带热镀锌产品为研究对象,研究了成分对成品热镀锌钢板质量的影响;并在成本控制的前提下,通过碳与磷成分的组合优化,提出了一套以碳锰设计为基础、兼顾产品质量的成分综合优化方案。将综合优化方案应用到某钢铁企业的生产实践后,生产出了强度为320 MPa以上、表面无色差等缺陷的镀锌薄板产品,满足了家电裸用的要求,且给企业创造了较大的经济效益,具有进一步推广应用的价值。 相似文献
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Rud' Viktor D. Lotish Vladimir V. Gumenyuk Larisa A. 《Powder Metallurgy and Metal Ceramics》2002,41(5-6):260-263
Studies have been made on the effects of the fractional composition in a bidispersed mixture on the porosity in the formation of filters by free pouring. A nomogram has been drawn up for the dependence of the porosity on the component contents and sizes. A method is proposed for forecasting the porosity from the component contents. A rapid computer method has been developed for establishing the porosities of planar items. 相似文献
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Xinjian Duan Mukesh Jain David S. Wilkinson 《Metallurgical and Materials Transactions A》2006,37(12):3489-3501
A heterogeneous finite element model with randomly distributed inhomogeneities has been developed for the determination of
the forming limit diagram (FLD) for thin aluminum sheet material based on the prediction of localized necking. The strength
difference between the inhomogeneities and the matrix is ascertained either from the fluctuation of the experimental stress-strain
curve or from a micromechanical analysis that uses a representative particle field. By changing the specimen geometry and
friction conditions, different stress states (or strain paths) are achieved. A plot of the critical Oyane fracture parameter
is used to identify the limit strain state. Also, a plot of equivalent plastic strain rate is used to distinguish the boundary
of intense shear bands and hence to identify where to take the measurement point. Both a plane stress model and a three-dimensional
(3-D) model are adopted to predict the shear banding phenomenon and hence the FLD. The predicted FLD agrees well with the
measurements from a recent round robin experimental FLD involving several independent research laboratories. The Taguchi method
is applied to assess how the various parameters involved in the heterogeneous model affect the calculated forming limit strain. 相似文献
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Thermophysical properties of roll-compacted nickel sheet for high-density infrared sheet fabrication
J. D. K. Rivard A. S. Sabau C. A. Blue E. K. Ohriner N. Jayaraman 《Metallurgical and Materials Transactions A》2003,34(12):3043-3054
This work is focused on the analysis of the high-density infrared (HDI) sheet fabrication process of powder compacts. Measurements
of material properties and distribution of incident heat flux on processed powder sheet surfaces have been conducted with
the aim of obtaining a complete set of data that can be used as input in computer simulation software. It was found that these
materials exhibit significant anisotropy in thermal conductivity. Indirect measurements indicate that there are small variations
in density across the thickness of the powder compacts. Temperature data were obtained from thermocouples placed on the backside
of the sheet. The evolution of thermal profile during a static pulse was investigated by using a three-dimensional finite
volume model. Numerical simulation results are very sensitive to the surface emissivity. Numerical simulation results agree
very well with experimental results for the case in which no liquid pool was formed during HDI processing. 相似文献
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介绍了自动称量包装机器人在莱钢焦化厂硫铵生产中的应用及其取得的经济效益和社会效益。 相似文献
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V. L. Mazur 《Steel in Translation》2012,42(4):348-352
Temper rolling with relatively small deformation (usually around 1%) forms the final mechanical properties, planarity, and surface microrelief of sheet steel. The aspects of temper rolling that affect the final strip quality may be identified on the basis of theoretical and experimental data and production experience with hot- and cold-rolled thin-sheet steel at various metallurgical enterprises. Practical recommendations are made regarding temper rolling. 相似文献