取向硅钢二次再结晶机理研究的进展

取向硅钢二次再结晶的机理是涉及到材料的成分及热轧、冷轧、初次再结晶退火和最终高温退火等一系列工艺过程的复杂问题。几十年来,许多冶金工作者曾在这一领域进行了大量的研究工作,并取得了很大进展。近年来,由于实验技术的进步,更加深了对这一问题的认识。本文在对有关的早期工作进行简要回顾总结的基础上,重点对近年来的一些最新研究结果以及提出的新理论做了较为系统的介绍。     

Fatigue Strength Improvement of Welded Joint by Ultrasonic Peening in Ultra-Fine Grain Steel

Thefatiguestrengthisthemostimportantser vicepropertyofaweldedjoint .Duetotheexistenceoftensileresidualstressesand geometricaldisconti nuityacrosstheweld ,thefailurenormallyoccursattheweldedjoint .Hence ,itiscommonforimportantstructurestoapplyastressrelievingheattreatmentafterwelding .Thisis ,however ,prohibitedforweldedjointsinultra finegrainsteels .Thegrainre finementistheonlystrengtheningmethodthaten hancesbothstrengthandtoughness .IntheNationalKeyFundamentalResearchDevelopmentProject“th…     

Studies of interfaces in Al65Cu20Fe15

The study of interfaces in quasicrystalline alloys is relatively new. Apart from the change in orientation, symmetry and chemistry which can occur across homophase and heterophase boundaries in crystalline materials, we have the additional, exciting possibility of an interface between quasicrystalline and its rational approximant. High resolution electron microscopy is a powerful technique to study the structural details of such interfaces. We report the results of a HREM study of the interface between the icosahedral phase and the related Al₁₃Fe₄ type monoclinic phase in melt spun and annealed Al₆₅Cu₂₀Fe₁₅ alloy.     

The influence of neutron irradiation on (B0.65C0.35)Ba1.4Sr0.6Ca2Cu3Oz superconducting phase: The role of the grain edge

Using the transport and magnetization measurements, the influence of neutron irradiation at a fluence of 5 × 10¹⁷ n cm⁻² on (B_0.65C_0.35)Ba_1.4Sr_0.6Ca₂Cu₃O _z has been investigated. The neutron irradiation was found to decrease critical temperature and transport critical current density, increase the residual and normal state resistivity, and improve the intragranular critical current density with 1.6 × 10⁵ A/cm² (at 77.3 K and in the applied field up to 160 kA m) and ΔM _irr/ΔM _nonirr ratio (up to factor of 3) at highest field used for investigation. The field dependence of this ratio, which is below the unity at very low field but higher than 1 at high fields, correlated with the shape of the hysteretic loops as well as with the change of the transport parameters after irradiation suggests the role of the irradiation-induced effects on the grain edges. We discuss these effects in the framework of the Bean-Livingstone surface barriers and geometrical barriers.     

Differences in polymeric proteins among grains in spring wheat spikes

A uniform amount and size distribution of polymeric proteins within grains in a spike might determine the stability of wheat quality. Two cultivars were grown to maturity in solution culture in a climate chamber. Nitrogen (N) in the form of nitrate was added daily and replaced with ¹⁵N before harvest. Plants were harvested during grain development. Protein composition and relationships of labelled N in grains from different spikelets within the spike were determined. Higher percentages of large unextractable polymeric proteins (%‐LUPP) and total unextractable polymeric proteins (%‐TUPP) were found in the lower‐ and uppermost spikelets in the spike compared with the middle ones for cv. WL, but not for cv. Sport. Both cultivars showed variations in the percentage of large unextractable monomeric proteins (%‐LUMP) and total SDS‐extractable protein (Tote) in the spikelets within the spike. The amount of total SDS‐unextractable protein (Totu) did not vary for either of the cultivars. The spikelets within the spike showing high and low %‐LUMP and Tote at maturity showed a similar behaviour shortly after flowering in cv. WL, but not in cv. Sport. The N concentration of SDS and sonicated extracts varied along the spikelets of the spike for both cultivars. The atom‐% excess ¹⁵N decreased in cv. Sport SDS‐extractable and ‐unextractable proteins and cv. WL albumins + globulins, gliadins and glutenins from grains at different spikelet positions along the spike. Copyright © 2005 Society of Chemical Industry     

用产出剖面资料求剩余油饱和度的方法研究

为了提供可靠的理论依据解决文东油田的开采矛盾 ,从反演角度出发 ,利用产出剖面资料所得的含水率来求取储层的剩余油饱和度。把该方法的计算结果和同一时期新投产的裸眼井解释结果进行比较 ,两者基本一致 ,说明该方法能较准确地反映地下的实际情况。     

Cr17铁素体不锈钢的应变速率脆性

研究了Cr17铁素体不锈钢在高温拉伸试验过程中应变速率对合金断面收缩率的影响,并对其发生机制进行了分析。合金在500℃下以不同应变速率(1.43×10-6~1.33s-1)拉伸至断裂,测试断面收缩率,并利用电子探针对晶界成分进行了观察测试。结果表明:应变速率从1.43×10-6 s-1升高至1.43×10-2 s-1,断面收缩率降低,约在1.43×10-2 s-1时达到最低值。然后,随着应变速率增加至1.33s-1,断面收缩率升高。经电子探针测试证实,断面收缩率达到最低值的样品,硫在晶界上偏聚,其他应变速率拉伸的样品没有观察到硫的晶界偏聚。基于多晶金属弹性变形的微观理论,分析这些试验结果,证实了此合金在拉伸试验中具有应变速率脆性的基本特征——临界应变速率。