Pub Date : 1900-01-01DOI: 10.1179/030634571790439351
A. J. Markworth, E. M. Baroody
AbstractAn analytical treatment is presented of the precipitation kinetics of inert-gas bubbles in solids, with emphasis upon the behaviour of the variance of the distribution of bubble radii. Using a modified van der Waals equation of state, it is shown that the variance decreases as precipitation proceeds, its square root varying approximately linearly with the reciprocal of the mean bubble radius. Results of the analysis are in good accord with published data describing the growth of small bubbles in UO2.
{"title":"Size-Distribution Effects in the Precipitation of Inert-Gas Bubbles in Solids","authors":"A. J. Markworth, E. M. Baroody","doi":"10.1179/030634571790439351","DOIUrl":"https://doi.org/10.1179/030634571790439351","url":null,"abstract":"AbstractAn analytical treatment is presented of the precipitation kinetics of inert-gas bubbles in solids, with emphasis upon the behaviour of the variance of the distribution of bubble radii. Using a modified van der Waals equation of state, it is shown that the variance decreases as precipitation proceeds, its square root varying approximately linearly with the reciprocal of the mean bubble radius. Results of the analysis are in good accord with published data describing the growth of small bubbles in UO2.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125278960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1179/030634568790443567
R. Bullough, J. T. Stanley, J. Williams
Abstract The initial kinetics for the migration of interstitial impurity atoms to a distribution of small dislocation loops has been evaluated and compared with the measured kinetics of Stage III recovery in neutron-irradiated niobium containing oxygen impurity. Both the theoretical calculation and the relevant electrical-resistivity measurements are presented. The agreement is very good and provides strong support for the assumption that the Stage III recovery is due to the migration of oxygen to the dislocation loops introduced by the irradiation.
{"title":"The Kinetics of Migration of Impurities to Small Dislocation Loops","authors":"R. Bullough, J. T. Stanley, J. Williams","doi":"10.1179/030634568790443567","DOIUrl":"https://doi.org/10.1179/030634568790443567","url":null,"abstract":"Abstract The initial kinetics for the migration of interstitial impurity atoms to a distribution of small dislocation loops has been evaluated and compared with the measured kinetics of Stage III recovery in neutron-irradiated niobium containing oxygen impurity. Both the theoretical calculation and the relevant electrical-resistivity measurements are presented. The agreement is very good and provides strong support for the assumption that the Stage III recovery is due to the migration of oxygen to the dislocation loops introduced by the irradiation.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132727400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1179/030634573790445677
C. Roques-carmes, M. Aucouturier, P. Lacombe
AbstractEmbrittlement and/or penetration of aluminium grain boundaries by liquid gallium have been investigated by a radiotracer technique and measurement of mechanical properties. A distinction is made between penetration without external stress and the embrittlement itself. However, the results show that a description of grain-boundary embrittlement must take into account the preliminary step of intergranular penetration by gallium. Moreover, two stages must be distinguished in the penetration of gallium; the driving force of the first stage seems to be a strong interaction between gallium and the grain boundaries. This interaction is usually described as intergranular adsorption. A general scheme for aluminium grain-boundary embrittlement and/or penetration is proposed. Some observations on the microstructure of the grain-boundary surfaces separated by liquid gallium are also reported. This technique of intergranular embrittlement by liquid gallium provides a new means of examining the structure of int...
{"title":"The Influence of Testing Temperature and Thermal History on the Intergranular Embrittlement and Penetration of Aluminium by Liquid Gallium","authors":"C. Roques-carmes, M. Aucouturier, P. Lacombe","doi":"10.1179/030634573790445677","DOIUrl":"https://doi.org/10.1179/030634573790445677","url":null,"abstract":"AbstractEmbrittlement and/or penetration of aluminium grain boundaries by liquid gallium have been investigated by a radiotracer technique and measurement of mechanical properties. A distinction is made between penetration without external stress and the embrittlement itself. However, the results show that a description of grain-boundary embrittlement must take into account the preliminary step of intergranular penetration by gallium. Moreover, two stages must be distinguished in the penetration of gallium; the driving force of the first stage seems to be a strong interaction between gallium and the grain boundaries. This interaction is usually described as intergranular adsorption. A general scheme for aluminium grain-boundary embrittlement and/or penetration is proposed. Some observations on the microstructure of the grain-boundary surfaces separated by liquid gallium are also reported. This technique of intergranular embrittlement by liquid gallium provides a new means of examining the structure of int...","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"364 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133301489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1179/030634568790443440
J. Evans, R. Rawlings
AbstractTensile tests have been made on mild-steel specimens with a range of grain sizes. Suppression of the yield point for the purpose of observing the early stages of work-hardening was accomplished by decarburizing in wet hydrogen or by quenching from 700°C. Analysis of the results indicates that there are two regions of work-hardening, which operate below and above 10% elongation, respectively. During the first stage, where work-hardening is parabolic, the rate of hardening varied with grain size. This was interpreted in the light of recent experimental observations relating flow stress and dislocation density, enabling an equation to be written that describes the flow stress in terms of grain size and plastic strain for the first 10% of elongation.
{"title":"The Grain-Size-Dependence of Flow Stress in Mild Steel","authors":"J. Evans, R. Rawlings","doi":"10.1179/030634568790443440","DOIUrl":"https://doi.org/10.1179/030634568790443440","url":null,"abstract":"AbstractTensile tests have been made on mild-steel specimens with a range of grain sizes. Suppression of the yield point for the purpose of observing the early stages of work-hardening was accomplished by decarburizing in wet hydrogen or by quenching from 700°C. Analysis of the results indicates that there are two regions of work-hardening, which operate below and above 10% elongation, respectively. During the first stage, where work-hardening is parabolic, the rate of hardening varied with grain size. This was interpreted in the light of recent experimental observations relating flow stress and dislocation density, enabling an equation to be written that describes the flow stress in terms of grain size and plastic strain for the first 10% of elongation.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133448464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1179/MSC.1967.1.1.166
M. D. Morton, G. Leak
AbstractStrong damping and modulus effects have been observed using a torsional pendulum in very pure, coarse-grained copper, gold, and seven completely miscible copper-gold alloys. In Cu and Au a high-temperature relaxation peak increases with increasing grain size and stabilizes at 470 and 230 degC, respectively, above the orthodox grain-boundary damping peaks. Related damping peaks were also measured in the alloys with activation energies distributed between Cu and Au, decreasing with increasing Au content. All alloys showed stronger relaxation effects than pure Cu and Au, with a maximum at cu3Au. It is suggested that this high-temperature peak results from grain-boundary sliding and that the relaxation time and strength in Cu and Au are controlled by irregularities in the grain boundaries. Adsorption of solute atoms on the alloy boundaries will influence these irregularities and facilitate greater sliding.
{"title":"Grain-Boundary Relaxations in Copper-Gold Alloys","authors":"M. D. Morton, G. Leak","doi":"10.1179/MSC.1967.1.1.166","DOIUrl":"https://doi.org/10.1179/MSC.1967.1.1.166","url":null,"abstract":"AbstractStrong damping and modulus effects have been observed using a torsional pendulum in very pure, coarse-grained copper, gold, and seven completely miscible copper-gold alloys. In Cu and Au a high-temperature relaxation peak increases with increasing grain size and stabilizes at 470 and 230 degC, respectively, above the orthodox grain-boundary damping peaks. Related damping peaks were also measured in the alloys with activation energies distributed between Cu and Au, decreasing with increasing Au content. All alloys showed stronger relaxation effects than pure Cu and Au, with a maximum at cu3Au. It is suggested that this high-temperature peak results from grain-boundary sliding and that the relaxation time and strength in Cu and Au are controlled by irregularities in the grain boundaries. Adsorption of solute atoms on the alloy boundaries will influence these irregularities and facilitate greater sliding.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"2000 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133975732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1179/030634573790445325
G. J. Lloyd, J. Martin
AbstractIn a previous paper we calculated the diffusion constants of oxygen in nickel using an abridged form of a treatment due to Meijering and Druyvesteyn. Since that publication, a value for the diffusivity of beryllium in nickel has been brought to our attention and accordingly more correct values can be calculated.
{"title":"The Diffusivity of Oxygen in Nickel Determined by Internal Oxidation of Dilute Ni–Be Alloys","authors":"G. J. Lloyd, J. Martin","doi":"10.1179/030634573790445325","DOIUrl":"https://doi.org/10.1179/030634573790445325","url":null,"abstract":"AbstractIn a previous paper we calculated the diffusion constants of oxygen in nickel using an abridged form of a treatment due to Meijering and Druyvesteyn. Since that publication, a value for the diffusivity of beryllium in nickel has been brought to our attention and accordingly more correct values can be calculated.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114405330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1179/030634568790443468
B. Beeston, I. Dillamore, R. Smallman
AbstractStacking-fault energy measurements on nickel-cobalt alloys, obtained by three different methods, have been compared. The combined results from the node and empirical texture methods differ from those obtained by the tetrahedron method, which are consistently lower though showing the same form of variation with composition. The discrepancy is critically discussed and a probable value of 240 ± 50 ergs/cm2 obtained for the stacking-fault energy of nickel.
{"title":"The Stacking-Fault Energy of Some Nickel-Cobalt Alloys","authors":"B. Beeston, I. Dillamore, R. Smallman","doi":"10.1179/030634568790443468","DOIUrl":"https://doi.org/10.1179/030634568790443468","url":null,"abstract":"AbstractStacking-fault energy measurements on nickel-cobalt alloys, obtained by three different methods, have been compared. The combined results from the node and empirical texture methods differ from those obtained by the tetrahedron method, which are consistently lower though showing the same form of variation with composition. The discrepancy is critically discussed and a probable value of 240 ± 50 ergs/cm2 obtained for the stacking-fault energy of nickel.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124953195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
AbstractA high-temperature relaxation peak (H.T.P.) has been observed at T(°K) ≥ 0·5 Tm in the damping spectra of pure silver and pure copper, in large-grained wire specimens. The relaxation strength of the peak in copper was ∼ 8 times larger than that for silver, though the incidence of “bamboo” grain boundaries was comparable. The occurrence of the peak was associated with the development of a “bamboo” grain structure and was attributed to the reversible shear or glide of boundaries at high temperatures, coupled with the movement of boundary jogs. Trace impurities rapidly suppressed the peak, this phenomenon being explained in terms of the impurity atoms poisoning the jogs and inhibiting their movement.
{"title":"On the High-Temperature Relaxation Peak in F.C.C. Metals","authors":"J. T. Roberts, P. Barrand","doi":"10.1179/MSC.1969.3.1.97","DOIUrl":"https://doi.org/10.1179/MSC.1969.3.1.97","url":null,"abstract":"AbstractA high-temperature relaxation peak (H.T.P.) has been observed at T(°K) ≥ 0·5 Tm in the damping spectra of pure silver and pure copper, in large-grained wire specimens. The relaxation strength of the peak in copper was ∼ 8 times larger than that for silver, though the incidence of “bamboo” grain boundaries was comparable. The occurrence of the peak was associated with the development of a “bamboo” grain structure and was attributed to the reversible shear or glide of boundaries at high temperatures, coupled with the movement of boundary jogs. Trace impurities rapidly suppressed the peak, this phenomenon being explained in terms of the impurity atoms poisoning the jogs and inhibiting their movement.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125068318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1179/030634572790446118
R. Ham, R. H. Cook, G. Purdy, G. Willoughby
AbstractEarlier work by R. K. Ham, R. H. Cook, and G. R. Purdy (Metal Sci. J, 1972, 6, 73) has demonstrated that it is possible to produce a precipitate of the disordered nickel-rich terminal solid solution, γ, in a matrix of the ordered γ′ phase Ni3 (Al,Ti). The present paper shows that this precipitate increases the steady-state creep-resistance of the matrix and induces a prolonged initial stage of very low creep rate (‘nilcreep stage’). The end of the nil-creep stage was associated with loss of coherency of the γ precipitate and an increase in matrix dislocation activity. A model is proposed in which the particles are treated as attractive trapping sites for superlattice dislocations, so that measurable deformation can occur only when Ostwald ripening has increased the particle spacing to a level sufficient for Orowan looping of dislocations between the particles. This model accounts for many of the observed features of the nil-creep stage.
R. K. Ham, R. H. Cook和G. R. Purdy(金属科学)的早期工作。J, 1972, 6,73)已经证明，在有序γ′相Ni3 (Al,Ti)的基体中有可能产生无序富镍末端固溶体γ的沉淀。本文表明，这种析出物增加了基体的稳态抗蠕变能力，并导致了极低蠕变速率的初始阶段(“零蠕变阶段”)的延长。蠕变阶段的结束与γ析出相的相干性丧失和基体位错活度的增加有关。提出了一种模型，其中粒子被视为超晶格位错的吸引捕获点，因此，只有当奥斯特瓦尔德成熟将粒子间距增加到足以使粒子之间的位错形成Orowan环的水平时，才会发生可测量的变形。该模型解释了许多观察到的零蠕变阶段的特征。
{"title":"The Influence of γ Precipitation upon the Creep of γ′ (Ni3 (Al, Ti)) Single Crystals","authors":"R. Ham, R. H. Cook, G. Purdy, G. Willoughby","doi":"10.1179/030634572790446118","DOIUrl":"https://doi.org/10.1179/030634572790446118","url":null,"abstract":"AbstractEarlier work by R. K. Ham, R. H. Cook, and G. R. Purdy (Metal Sci. J, 1972, 6, 73) has demonstrated that it is possible to produce a precipitate of the disordered nickel-rich terminal solid solution, γ, in a matrix of the ordered γ′ phase Ni3 (Al,Ti). The present paper shows that this precipitate increases the steady-state creep-resistance of the matrix and induces a prolonged initial stage of very low creep rate (‘nilcreep stage’). The end of the nil-creep stage was associated with loss of coherency of the γ precipitate and an increase in matrix dislocation activity. A model is proposed in which the particles are treated as attractive trapping sites for superlattice dislocations, so that measurable deformation can occur only when Ostwald ripening has increased the particle spacing to a level sufficient for Orowan looping of dislocations between the particles. This model accounts for many of the observed features of the nil-creep stage.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125185540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1179/030634573790445550
J. Robinson, C. Beevers
AbstractLow-stress fatigue-crack-propagation tests have been carried out on three commercially pure α-titaniumalloys. It was found that decreasing load ratio (R), increasing grain size, and increasing interstitial alloying content could all produce significant reductions in growth rate over the ∆K range studied (4–20 MN/m2). The conclusion was reached that the fatigue-fracture process comprised two stages: (1) the formation of relatively planar facets (primarily ∆K-controlled) and (2) their interconnection by a mechanism involving plastic tearing (primarily K max-controlled). Scanning electron microscope examination of the fatigue-fracture surfaces revealed that the orientations of individual grains exerted a considerable influence on fracture-surface morphology. This effect occurred when the scale of reversed plasticity at the crack tip was of the order of, or less than, the grain size. A transition in fracturesurface appearance occurred in all specimens at an approximately constant value of growth rate ...
{"title":"The Effects of Load Ratio, Interstitial Content, and Grain Size on Low-Stress Fatigue-Crack Propagation in α-Titanium","authors":"J. Robinson, C. Beevers","doi":"10.1179/030634573790445550","DOIUrl":"https://doi.org/10.1179/030634573790445550","url":null,"abstract":"AbstractLow-stress fatigue-crack-propagation tests have been carried out on three commercially pure α-titaniumalloys. It was found that decreasing load ratio (R), increasing grain size, and increasing interstitial alloying content could all produce significant reductions in growth rate over the ∆K range studied (4–20 MN/m2). The conclusion was reached that the fatigue-fracture process comprised two stages: (1) the formation of relatively planar facets (primarily ∆K-controlled) and (2) their interconnection by a mechanism involving plastic tearing (primarily K max-controlled). Scanning electron microscope examination of the fatigue-fracture surfaces revealed that the orientations of individual grains exerted a considerable influence on fracture-surface morphology. This effect occurred when the scale of reversed plasticity at the crack tip was of the order of, or less than, the grain size. A transition in fracturesurface appearance occurred in all specimens at an approximately constant value of growth rate ...","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131555224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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