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101.
Chao-Hong Wang Sinn-Wen Chen Chia-Hua Chang Jen-Chin Wu 《Metallurgical and Materials Transactions A》2003,34(2):199-209
A series of Al-Cu-Ni alloys of various compositions were made and annealed at 800 °C. The equilibrium phases were studied
by metallography, X-ray diffraction (XRD) analysis, and electron probe microanalysis. The isothermal section of the ternary
Al-Cu-Ni system at 800 °C was then determined based on these experimental results and the available phase relationship knowledge
of the three constituent binary systems. No ternary compound was found. All three phases, AlNi3, AlNi, and Al3Ni2, have very high ternary solubility, especially the AlNi phase, which almost reaches the binary Al-Cu side. However, no continuous
solid solution was formed between the AlNi phase and any of the binary Al-Cu phases. Interfacial reactions of Al/Ni, Al/Cu,
Al-Cu/Ni, and Al-Ni/Cu at 800 °C were investigated by using reaction couple techniques. The results showed that Al3Ni and Al3Ni2 phases were formed in the Al/Ni couples; β-AlCu4, γ
1-Al4Cu9, and ɛ
2-Al2Cu3 phases were formed in the Al/Cu couples. As for the results in the Al-2 at. pct Ni/Cu, Al-5 at. pct Ni/Cu, and Al-2 at. pct
Cu/Ni, Al-4.5 at. pct Cu/Ni, and Al-6 at. pct Cu/Ni were similar to those in the binary Al/Cu and Al/Ni couples, respectively.
A different reaction path was found in the Al-7.5 at. pct Cu/Ni couples, and an AlNi solid solution layer was formed instead
of the Al3Ni and Al3Ni2 phases. 相似文献
102.
103.
104.
Jon T. Carter Paul E. Krajewski Ravi Verma 《JOM Journal of the Minerals, Metals and Materials Society》2008,60(11):77-81
The hot blow forming of magnesium sheet offers significant opportunity for forming complex, lightweight parts for automotive
applications. This paper characterizes the elevated-temperature formability of AZ31 magnesium sheet materials and the effect
of processing conditions on the performance of these materials. In addition, magnesium sheet application development at General
Motors Corporation is reviewed. 相似文献
105.
Toshihiko Hoshide Junpei Fujita 《Journal of Materials Engineering and Performance》2008,17(5):627-632
Strength of ground ceramics may be affected by residual stress as well as surface flaws induced by grinding. Strength prediction
for ground ceramics is convenient for mechanical design of ceramic components. In this article, a numerical procedure based
on fracture mechanics was proposed to estimate strength distribution of ground ceramics by considering grinding-induced residual
stress. Bending strength and residual stress of ground ceramics were measured for three grinding-conditions. By comparison
of simulated results with experimental ones, it was revealed that strength characteristics in experiments were well simulated
by using the proposed procedure. 相似文献
106.
应用事故树法对深水井控进行风险评估 总被引:5,自引:0,他引:5
深水井喷事故危害极大,严重时可导致井眼报废、船毁人亡等恶性后果,预防和控制深水井喷是国内外石油界的一个技术难题。文中利用风险树分析引发深水钻井工程事故的顶事件,重点讨论各底事件的相互联系及对系统的影响程度,分析顶事件的发生概率,为最大程度地减少深水井控事故的发生提供理论依据。通过对深水钻井过程中存在的风险进行分析,构建了深水井控风险分析事故树,并对其进行了定性与定量分析。通过风险分析,认为深水井控最主要的影响因素是关井及压井时设备故障、设计方法及操作失误的影响超过安全极限。分析表明,降低基本事件的发生概率对预防井喷作用明显,基本事件发生概率提高1倍,井喷发生概率提高近10倍。针对深水井控过程中存在的风险因素,从工艺、装备及人员要求方面提出了预防深水井喷的措施。 相似文献
107.
借鉴模型参考控制器的设计思想,采用经过线性二次型输出反馈控制后的系统作为参考模型,以它的输出作为期望输出,让实际输出跟随这个期望输出;二者的误差信号反馈到原系统的输入端,设计出一种模型参考控制器.经该控制器优化后,电视导引头系统的快速性可得到较大提高.参考模型可由RC网络或计算机软件来实现. 相似文献
108.
109.
Zirconium(IV) tungstoiodophosphate has been synthesized under a variety of conditions. The most chemically and thermally stable
sample is prepared by adding a mixture of aqueous solutions of 0·5 mol L−1 sodium tungstate, potassium iodate and 1 mol L−1 orthophosphoric acid to aqueous solution of 0·1 mol L−1 zirconium(IV) oxychloride. Its ion exchange capacity for Na+ and K+ was found to be 2·20 and 2·35 meq g−1 dry exchanger, respectively. The material has been characterized on the basis of chemical composition, pH titration, Fourier
transform infrared spectroscopy (FTIR) and thermogravimetric analysis. The effect on the exchange capacity of drying the exchanger
at different temperatures has been studied. The analytical importance of the material has been established by quantitative
separation of Pb2+ from other metal ions. 相似文献
110.
Jonathan P. Belnoue Giang D. Nguyen Alexander M. Korsunsky 《International Journal of Fracture》2007,144(1):53-60
This paper presents a new 1-D non-local damage-plasticity deformation model for ductile materials. It uses the thermodynamic
framework described in Houlsby and Puzrin (2000) and holds, nevertheless, some similarities with Lemaitre’s (1971) approach.
A 1D finite element (FE) model of a bar fixed at one end and loaded in tension at the other end is introduced. This simple
model demonstrates how the approach can be implemented within the finite element framework, and that it is capable of capturing
both the pre-peak hardening and post-peak softening (generally responsible for models instability) due to damage-induced stiffness
and strength reduction characteristic of ductile materials. It is also shown that the approach has further advantages of achieving
some degree of mesh independence, and of being able to capture deformation size effects. Finally, it is illustrated how the
model permits the calculation of essential work of rupture (EWR), i.e. the specific energy per unit cross-sectional area that
is needed to cause tensile failure of a specimen. 相似文献