Alloys Part Research Articles

Mechanical properties of Al–Li alloys Part 1 Fracture toughness and microstructure

Abstract Mechanisms influencing the ambient temperature mechanical properties of commercial Al–Li alloys 2090, 8090, 8091, and 2091 are examined as a function of plate orientation, with specific emphasis on the role of microstructure. In Part 1, results on the uniaxial tensile and plane strain fracture toughness properties are presented and the behaviour is discussed in terms of the role of the matrix and grain boundary precipitates, associated precipitate free zones (PFZs), and the occurrence of short-transverse delamination. It is seen that in general peak aged microstructures show an excellent combination of strength and toughness (L–T, T–L), equal to or exceeding that shown by traditional 2000 and 7000 series high strength aluminium alloys. The superior toughness of peak aged compared with naturally aged microstructures seems to be associated with widespread matrix precipitation of platelike precipitates (T1 in Al–Li–Cu alloys and S in Al–Li–Cu–Mg alloys), β′-dispersoids and second phase particles whi...

A model for surface segregation in multicomponent alloys—part IV: The kinetics of desegregation in a binary alloy

A model developed to describe the kinetics of surface segregation in a binary alloy is used to explain the desegregation kinetics of a segregated overlayer. It is shown that the time dependence of the desegregation process is different from predictions from diffusion models but in agreement with experimental results. Some examples of desegregation behaviour are discussed using results from literature.

A model for surface segregation in multicomponent alloys—part III: The kinetics of surface segregation in a binary alloy

The kinetics of surface segregation in a binary alloy is described by setting up and solving a system of rate equations using the change in Gibbs free energy between adjacent cells as atoms are interchanged between these cells. It is shown that this description is consistent with both the thermodynamical approach for the calculation of equilibrium surface coverages and the kinetic approach solving Fick's equations. The effect of the different parameters is discussed explaining results from the literature.

A model for surface segregation in multicomponent alloys—part II: Comment on other segregation analyses

The Guttmann and other macroscopic thermodynamical analyses of surface segregation are discussed in terms of a model presented by the authors. Several inconsistencies in these descriptions are identified and discussed. The correct criteria for the occurrence of discontinuous transitions in the segregation isotherm and surface coverage vs temperature curves are presented.

Study on Grinding of Base Metals Alloys Part 3. Grinding of a Co-Cr Alloy under Constant Force

Study on Grinding of Base Metals Alloys Part 3. Grinding of a Co-Cr Alloy under Constant Force

Thermodynamic model of the solidification process of alloys part II—General treatment of segregation as the precipitation of a solid phase in a closed system

The microstructure in the fusion zone of 15-5 PH autogeneous laser beam welds revealed that the solidification mode is primary ferrite. Both primary ferrite and eutectic ferrite existed in the fusion zone. Primary ferrite was found to be in the vermicular morphology and located at the axes of the cells. Eutectic ferrite was roundish in nature and was located at the cell boundaries. Eutectic ferrite was identified with its location in the structure and it is associated with NbC and a niobium-containing Z-phase precipitate.The formation of a eutectic and the thermal phase stability of 15-5 PH was predicted from the Fe-Ni-Cr phase diagram for the nominal composition of the alloy from equal chemical potentials and differential mass balance equations. These equations were used to predict the solidification path and microsegregation patterns for iron, nickel and chromium for the case of complete mixing in the liquid. It was shown that the solidification mode is ferrite and that the liquid reaches the eutectic valley when the fraction of solid is 0.7.The precipitation hardening element and the phase were pure copper, and were coherent with the matrix both in the fusion zone and in the base metal. Generally, the fusion zone was found to be harder than the base metal.

Shape Memory Effect in Ti-base Alloys(Part 3) : Effect of Heat Treatment and Alloy Melting

Shape Memory Effect in Ti-base Alloys(Part 3) : Effect of Heat Treatment and Alloy Melting

Recrystallization features of ordered alloys part 2. Superstructures L1 2, B2 and L1 o

Etude a partir de resultats experimentaux anterieurs de trois surstructures Cu 3 Au pour L1 2 , FeCo-0,4% Cr pour B2 et NiPt pour L1 0 . On conclut que la mobilite des dislocations a l'interieur de la trame heritee pendant la transformation de phases est une condition indispensable pour la recristallisation

Electrocatalysis by Pd + Au alloys Part II. Electro-oxidation of formaldehyde in acidic and alkaline solutions

Au and Au-rich Pd + Au alloys were very active towards the electro-oxidation of HCHO in 1 M NaOH, exceeding that of Pt, but conversely entirely inactive in 0.05 M H 2SO 4. Further, the reaction rate in the former solution was already noticeable at potentials as low as 0.1 V RHE. The rate was higher at higher alkali and HCHO concentrations. These facts suggest that the HCHO electro-oxidation in alkaline media does not require oxygen species on the electrode surface but takes oxygen from OH − or H 2O. Thus, HCHO was concluded to be an excellent material for fuel cell applications. The Tafel slope indicated that the first charge-transfer step was rate-determining. The oxidation was still of significant rate in Na 2CO 3 solutions but much slower in KHCO 3 solutions.

歯科接着性レジン・パナビアＥＸの歯科用合金に対する接着強さ その２ 貴金属合金との接着について

歯科接着性レジン・パナビアＥＸの歯科用合金に対する接着強さ その２ 貴金属合金との接着について

Magnetic order in palladium-based Heusler alloys part 3: The effects of disorder in Pd 2MnIn 1− xSn and Pd 2MnIn 1− ySb

Magnetization, susceptibility, X-ray and neutron diffraction measurements have already been reported in parts 1 and 2 on the two alloy series Pd 2MnIn 1− x Sn x and Pd 2MnIn 1− y Sb y when chemically ordered in the Heusler structure, with the Mn atoms on an fcc sublattice and carrying a moment of about 4.2μ B ordered antiferromagnetically or ferromagnetically depending upon the conduction electron concentration. Results are presented here of similar measurements on the same samples, but after heat-treatments designed to produce maximum disorder between the Mn and In/Sn or In/Sb sites, respectively, whilst retaining the Pd order. In this disordered, B2, structure the Mn atoms retain the same magnetic moment but now occupy a simple cubic sublattice and form a new antiferromagnetic structure, simple cubic type 1. The results are discussed in terms of current indirect double resonance exchange interactions.

Magnetic order in palladium-based Heusler alloys Part I: Pd 2MnIn 1− xSn x and Pd 2MnSn 1− xSb x

Magnetization, susceptibility, X-ray and neutron diffraction measurements have been made on the two series of alloys Pd 2MnIn 1− x Sn x and Pd 2MnSn 1− x Sb x , for 0 ⩽ x ⩽ 1. All were single phase and were chemically ordered intermetallic compounds with the Heusler L2 1 structure in which the Mn atoms occupy an f.c.c. sub-lattice. At all compositions the alloys were magnetically ordered with a moment of ∼4.3 μ B located at the Mn sites. At the In-rich end the magnetic order is antiferromagnetic f.c.c. type 2. As Sn is increasingly substituted for In there is a change in magnetic order first to antiferromagnetic f.c.c. type 3A and then to ferromagnetism. All the alloys in the Sn/Sb series are ferromagnetic and in both series there is an increase in the ferromagnetic exchange interactions with increasing electron concentration.

Diffusion in copper and copper alloys part IV. Diffusion in systems involving elements of group VIII

A survey, comparison, and critical analysis is presented of data compiled from the scientific literature concerning diffusion in copper alloy systems involving elements in Group VII (Co, Fe, Ni, Pd, Pt, Rh, Ru). Here the term ’’copper alloy system’’ is interpreted in the broadest sense. For example, the review of diffusion in the Cu-M system reports all diffusion situations which involve both copper and element M. including diffusion of Cu in M or in any binary, ternary or multicomponent alloy containing M; diffusion of M in Cu or in any alloy containing Cu; and diffusion of any element in any alloy containing both Cu and M. Topics include volume diffusion, surface diffusion, grain boundary diffusion, tracer diffusion, alloy interdiffusion, electromigration, thermomigration, dislocation-pipe diffusion, and diffusion in molten metals. An extensive bibliography is presented along with figures, tabular presentation of data and discussion of results.

The electrochemical behaviour of lead/tin alloys—Part I. Studies in nitrate electrolytes

A series of lead/tin alloys have been examined in order to determine how alloy composition affects some important electrochemical characteristics. The behaviour is complex. Tin modifies the well-defined double layer structure of lead in a non-linear manner. A progression towards the double layer structure of tin is not observed, rather the interphase structure of the alloys appear always to be complicated by adsorption. Tin increases the reactivity of alloyed lead under certain conditions and transpassive dissolution of the alloy occurs in regions where pure lead itself would be expected not to dissolve. Exchange currents also behave in a rather anomalous manner. For the present the experiments can only be regarded as preliminary, however definite trends are indicated which themselves highlight further areas of worthwhile study.

Cyclic stress—strain response of two-phase alloys Part I. Microstructures containing particles penetrable by dislocations

Specimens of solution-treated Al-4% Cu alloy and aged alloy with coherent θ″ precipitates have been cycled under constant plastic strain over a wide range of fatigue life. The cyclic hardening and subsequent softening which occurs have been investigated by phenomenological experiments, electron and scanning microscopy and by optical microscopy. Hardening is interpreted by unidirectional concepts and softening by a disordering hypothesis, a new application with respect to fatigue. On the basis of these results, a general interpretation of cyclic response in this type of two-phase alloy has been obtained.

Cyclic stress—strain response of two-phase alloys Part II. Particles not penetrated by dislocations

Specimens of Al-4% Cu alloy with microstructures containing θ′ precipitates were cycled under constant plastic strain over a wide range of fatigue life. Cyclic response (hardening and saturation) was investigated by phenomenological experiments and by transmission and scanning microscopy. Applying unidirectional hardening mechanisms, we determined how the second phase controlled the cyclic response when the precipitates were closely spaced; and how the cyclic response approached that of single phase materials, when the interparticle spacing was equal to or greater than the self trapping distance of dislocations.

ChemInform Abstract: AN INTERSTITIAL‐ELECTRON MODEL FOR THE STRUCTURE OF METALS AND ALLOYS PART 4, MAGNETIC PROPERTIES OF METALS AND ELECTRONIC STRUCTURES OF GROUP VI‐VIII METALS

Chemischer InformationsdienstVolume 4, Issue 39 Physical Inorganic Chemistry ChemInform Abstract: AN INTERSTITIAL-ELECTRON MODEL FOR THE STRUCTURE OF METALS AND ALLOYS PART 4, MAGNETIC PROPERTIES OF METALS AND ELECTRONIC STRUCTURES OF GROUP VI-VIII METALS OLIVER JOHNSON, OLIVER JOHNSONSearch for more papers by this author OLIVER JOHNSON, OLIVER JOHNSONSearch for more papers by this author First published: September 25, 1973 https://doi.org/10.1002/chin.197339026Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume4, Issue39September 25, 1973 RelatedInformation

Electrolytic deposition of silicon and of silicon alloys Part III: Deposition of silicon and aluminum using a copper cathode

AbstractThe decomposition voltages of SiO2 and Al2O3 dissolved in cryolite were measured using a copper cathode. In a melt containing 90 wt% Na3AlF6 + 10 wt% Al2O3 at 1030°C the decomposition voltage of alumina was found to be Ed = 1.50 ± 0.05 V. In a melt containing 95 wt% Na3AlF6 + 5 wt% siO2 the value of the decomposition voltage was determined to Ed = 1.10 ± 0.05 V. In Na3AlF6-Al203-SiO2 mixtures the decomposition voltage of silica was found to increase with increasing concentration of alumina in the electrolyte.It was determined that at current densities below 0.2 A·cm−2 only silicon was deposited at the cathode whereas at higher current densities Si and Al were deposited simultaneously. The deposition ratio was found to depend on the current density.The distribution of silicon in the Si-Cu alloy was determined by spectroscopic analysis. It was found to be a function of the current density and of the diffusion rate of the deposited metal in the alloy. Resume Les auteurs mesurent sur cathode de cuivre...

Electrolytic deposition of silicon and of silicon alloys Part III: Deposition of silicon and aluminum using a copper cathode

Electrolytic deposition of silicon and of silicon alloys Part III: Deposition of silicon and aluminum using a copper cathode

Electrolytic deposition of silicon and of silicon alloys Part II: Decomposition voltages of components and current efficiency in the electrolysis of the Na<SUB>3</SUB>AlF<SUB>6</SUB>-Al<SUB>2</SUB>O<SUB>3</SUB>-SiO<SUB>2</SUB> mixtures

Electrolytic deposition of silicon and of silicon alloys Part II: Decomposition voltages of components and current efficiency in the electrolysis of the Na<SUB>3</SUB>AlF<SUB>6</SUB>-Al<SUB>2</SUB>O<SUB>3</SUB>-SiO<SUB>2</SUB> mixtures