The role of structural ledges at phase boundaries—III. F.C.C.-B.C.C. interfaces in Kurdjumov-Sachs orientation

The ledge mode of misfit accommodation is extended to {111} f.c.c.∥{110} b.c.c. interfaces with the Kurdjumov-Sachs (KS) orientation relationship. As with the Nishiyama-Wassermann (NW) relationship the geometric quantities are uniquely related by the misfit ratio r of atomic diameters. A rigid lattice analysis shows that the driving forces for a KS orientation relationship are significantly larger than those for the NW-x and even more so than those for the NW-y relationships. The rigid analysis also predicts that the terrace width which satisfies the periodicity conditions for a stepped interface are well within the terrace widths which allow significant energy gains. The models developed for the NW analysis are modified for KS configurations and employed to sum energies for the terrace patches, tilt misfit dislocations and the riser interface energy. Comparing this energy with that of a planar interphase boundary comprised of only misfit compensating dislocations shows that a stepped interphase boundary is energetically favored at r values near and greater than r_KS but less than r_NW-y.     

Structure-energy correlation for grain boundaries in f.c.c. metals—IV. Asymmetrical twist (general) boundaries

The zero-temperature energies and equilibrium volume expansions of pont-defect free asymmetrical grain boundaries (GBs) in f.c.c. bicrystals have been determined using both an embedded-atom-method potential fitted to Au and a Lennard-Jones potential fitted to Cu. The boundaries chosen involve one of the four densest planes on one side of the interface and a higher-index plane on the other. For both potentials it is found that the two asymmetrical tilt GBs at the endpoints of the GB-energy vs twist-misorientation curves give rise to pronounced energy cusps. These cusps are probably the main reason for the dominating appearance of tilt boundaries in rotating sphere-on-a-plate experiments, in spite of the fact that these boundaries represent an infinitely small subset in the total misorientation space comprised by the five macroscopic parameters needed to specify a general grain boundary. A comparison with earlier work on symmetrical GBs suggests that, except for the two densest lattice planes, symmetrical configurations may have higher energies than asymmetrical GBs with a densest plane on one side of the interface. A practically linear correlation between the energy of a GB and its volume expansion is observed, similar to that for the symmetrical GBs investigated earlier.     

C.C.C.轧机的工艺及结构特点

介绍了唐钢高速线材厂从美国birdsboro公司的紧凑式粗轧机的主要工艺参数和工艺、结构特点，提出了堆钢事故解决办法，展望了C．C．C．轧机的发展前景。     

Kinetics of F.C.C. → B.C.C. heterogeneous martensitic nucleation—I. The critical driving force for athermal nucleation

Employing available experimental data for athermal f.c.c. → b.c.c. martensitic transformation in binary, ternary and multicomponent Fe-base alloys, a model is developed and tested for the critical driving force at the M_s temperature. Incorporating the theory of solid solution hardening, we describe the composition dependence of the athermal frictional work for martensitic interface motion governing the kinetics of barrierless heterogeneous nucleation. The available data suggests that the composition dependence of the athermal frictional work is of the same form as that for slip deformation. We have evaluated the athermal strengths of 14 alloying elements Al, C, Co, Cr, Cu, Mn, Mo, N, Nb, Ni, Si, Ti, V and W from the experimental data. Except for Al, Ni and Co, the athermal strengths of the common substitutional alloying elements are similar in magnitude, while the interstitial solutes C and N exert a stronger influence. Previously proposed superposition laws are used to account for the presence of multiple solutes having different athermal strengths. With an improved assessment of the magnetic parameters of alloy systems, the model predicts M_s temperatures within ±40 K for M_s > 300 K where thermal contributions to the frictional work can be neglected.     

Study of energy vs misorientation for grain boundaries in gold by crystallite rotation method—I. [001] Twist boundaries

Small gold crystallites (~ 50–80 nm dia) were welded to thin film [001] single crystal gold substrates at a series of predetermined [001] twist angles in the range 0–45°. A pure [001] twist boundary therefore existed in each welded neck region which could be observed directly by transmission electron microscopy at normal incidence. Upon annealing, the crystallites rotated around [001] when the boundary energy varied with θ. The crystallites rotated into three misorientations corresponding to the special ∑1 and ∑5 misorientations and a symmetry related misorientation at θ = 45°. These results indicate the existence of grain boundary dislocation (GBD) related cusps on the boundary energy vs θ curve at ∑1 and ∑5. The rotations occurred conservatively by the motion of screw GBDs which could be observed directly by the transmission microscopy in certain regimes of θ. The results are relevant to recent calculations of the energies of [001] twist boundaries and the applicability of the GBD/structural unit model for grain boundaries.     

H.C.斯塔克集团概况

Ｈ．Ｃ．斯塔克集团为世界著名的难熔、硬质合金制品公司。本文对该公司的基本情况和发展现状作了简要介绍。     

Grain boundaries in Ni3Al—I. The local compositional order

The local compositional order in the vicinity of grain boundaries in Ni₃Al, with and without boron, was examined using lattice imaging techniques. It was shown that small angle twist, tilt and mixed boundaries and large angle (near Σ = 5) twist boundaries were ordered up to very close to the interface plane. A compositionally disordered region ∼ 1.5 nm thick is present in the vicinity of a large angle general boundary in boron-doped Ni₃Al. Two large angle general boundaries are ordered up to very close to the interface in boron-free Ni₃Al. Image simulations were performed to identify possible imaging artifacts due to inclination of the boundary plane away from being edge-on. It was shown that the experimental observations of a locally disordered region cannot be explained as being an imaging artifact.     

A.C.L顶燃式热风炉生产实践

A.C.L顶燃式热风炉通过冷铁半年来的工业试验,初步证实炉顶环形燃烧器具有燃烧均匀,安全、可靠,点火容易;炉体结构对称,炉内气流分布均匀,送风能力强等特性。文章肯定了该顶燃炉是一种高效、长寿、经济、合理的高风温热风炉。     

P.C.悬臂撞击式钢坯打印机

攀钢初轧厂为了加强钢坯的管理,确保产品质量,消除工人繁重的体力劳动,初步研制成功了P.C.悬臂撞击式钢坯打印机.这种打印机的打印程序是:由人工操纵按钮,使打印锤下落到最低位置.当大剪过来的钢坯以1～2米/秒的速度撞击带有字码的、具有一定重量的锤头时,钢坯就打上了印.同时,通过自动提升控制机构接通风阀电磁线圈并推动风缸,快速抬起锤头到原始位置,这就完成了一个打印程序.如果需打A段就落A锤,需打B段则落B锤,要打C段就将两锤同时落下.这种打印机简化了操作程序,实现了钢坯运动中的打印.     

V.C.R采矿法及工艺设计

V.C.R法是垂直深孔球形药包爆破后退式采矿法的简称。该方法的主要特点是:整个采场高度用潜孔钻机,按合理的孔网,从采场顶部凿岩硐室向下部水平拉底空间钻凿垂直或倾斜深孔(一般孔径为φ150～φ165毫米,普遍采用φ165毫米),然后采用高密度、高威力、高爆速、低感度的炸药,以球形药包(药包长度为直径的6倍以内),自下而上进行单分层或多分层爆破,并采用高效率的出矿设备(如铲运机),将爆下的矿石通     

用N.M.C.法分离钴和镍

用2-乙基-1-己基磷酸单2-乙基-1-己基脂(M2EHPA)从硫酸镍溶液中分离钴的方法进行了研究。M2EHPA的分离系数比D2EHPA大很多倍(D2EHPA是熟知的一种阳离子交换萃取剂)。 使用3级混合澄清装置,将含20％(体积)M2EHPA的有机试剂与含30克/升镍和12克/升钴的原始水溶液接触后,能获得这样的结果:萃余相含29.9克/升镍和0.002克/升钴,萃取相含0.14克/升镍和12克/升钴。将萃取相与含有CoSO_4的洗涤液混合,能有效地从有机相中除掉镍;与稀硫酸溶液接触很容易从有机相中反萃取出钴。在工业性设备中,是使用钴电解工序的废电解液作为反萃取液。使用N.M.C.法,反萃取液中的钴浓度被控制在100克/升左右。 根据本研究的结果,建立了一种分离钴和镍的方法。日本矿业公司利用这种方法,目前已能有效地分别生产出1300吨/年和3300吨/年高纯的钴和镍。     

Cold work hardening in stages IV and V of F.C.C. metals—I. Experiments and interpretation

The paper presents numerous measurements which confirm stages IV and V to be general ranges of cold work deformation. Analogous to stage II, stage IV exhibits a linear athermal hardening with constant strain rate sensitivity and activation enthalpy. In stage IV the dislocation cell size is constant, while the dislocation density growth rate is markedly reduced compared with stages II and III. Features of stage V are analogous to stage III, the increase of strain rate sensitivity (decrease of activation enthalpy) indicating the onset of thermally activated dislocation annihilation. In stage V, the mechanism is identified as dislocation climb from observing subgrain formation and saturation in density of deformation induced vacancies. Comparisons with recent investigations of stage IV and V at high temperatures suggest a common picture of low and high temperature deformation which only requires principles of storage and annihilation for both screw and edge dislocations.     

Nursing visibility: could the I.C.N.P. help?]

The present article discusses the visibility of Nursing care through the use of a Nursing classification "International Classification of Nursing Practice, proposed by the International Council of Nurses (ICN). The usefulness of a specific classification is discussed and comparison with the medical classifications are reasoned. Examples of experimentation are brought for sustaining the utility of the ICNP in the clinical practice, in education, in the Nursing management and in politics. To have a common language world-wide sustains the development of the discipline and the empowerment of Nursing profession.     

Grain boundarues in Ni3Al—II. The dislocation structure of small angle boundaries

The dislocation structure of small angle tilt and twist boundaries in ordered Ni₃Al, with and without boron, was investigated using transmission electron microscopy. Dislocations with Burgers vectors that correspond to anti-phase boundary (APB)-coupled superpartials were found in small angle [001] twist boundaries in both boron-free and boron-doped Ni₃Al, and a small angle [011] tilt boundary in boron-doped Ni₃Al. The boundary structures are in agreement with theoretical models proposed by Marcinkowski and co-workers. The APB energy determined from the dissociation of the grain boundary dislocations was lower than values reported for isolated APBs in Ni₃Al. For small angle twist boundaries the presence of boron reduced the APB energy at the interface until it approached zero. This is consistent with the structure of these boundaries containing small regions of increased compositional disorder in the first atomic plane next to the interface.     

H.C.Starck公司销售额持续高速增长

H.C.Starck公司的销售额从2010年的6.893亿欧元,增长到了2011年的8.832亿欧元,同比增长了28%,营业利润也比上年有了显著的增长。H.C.Starck公司的管理委员会主席Andreas Meier说:"2011年是H.C.Starck公司取得重要成就的一年,我们超额完成了H.C.Starck公司制定的战略性的和阶段性实际     

C.W.帕里预见新型铝的发展

美国阿尔考公司主席和主要负责人C.W.帕里在弗吉尼亚大学铝合金国际会议上发言中说:“对铝完全能和其它材料接合这一发现,我认为还缺乏足够的依据。”铝工业在下一个世纪的技术发展将取决于工业界和学术界对基础材料和应用的研究。查理强调指出:铝工业界的工程技术专家和理论家需要进行交流。     

Cold work hardening in stages IV and V of F.C.C. metals—II. Model fits and physical results

The paper presents a common concept for work hardening of f.c.c. metals at temperatures below 0.5 T_m up to very high strains. The concept considers statistical dislocation dynamics in terms of screw and edge dislocations and their specific interactions, and also allows for deformation-induced vacancies. By fitting the concept equations to experiment and using measured interaction parameters, very good agreement with strengthening data and dislocation densities of Cu and Al is achieved. The resulting fit parameters exhibit the expected order of magnitude and temperature dependence of dislocation storage and annihilation, for each dislocation type. The annihilation parameter of edge dislocations yields vacancy migration enthalpies of ≈0.2 eV for CU and Al indicating core migration of vacancies. From this the vacancy concentration is calculated for all strains and temperatures in question. Up to ≈0.3 T_m, the saturation concentration of vacancies decreases, but reincreases beyond this temperature following the thermal vacancy concentration.