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: 10.1179/030634572790445984
L. C. E. Geniets, J. F. Knottt
AbstractConventional measurements of the degree of temperembrittlement suffered by a steel are made in terms of the shift of the notched-bar “fracture appearance” transition temperatures (FATT). Any fundamental explanation of temperembrittlement must be concerned with the lowering of grain-boundary cohesion by the segregation of impurity. elements to grain boundaries over a critical temperature range, typically 560–430° C. The use of transition shifts to estimate the kinetics of reduction of grain-boundary cohesion can be criticized on several counts. First, it is often the case that the unembrittled condition breaks by cleavage rather than by intergranular fracture at low temperatures, so that no measure of the unembrittled grain-boundary cohesion can be obtained. Secondly, even if both fractures are intergranular, the shift compares fracture events at different temperatures and there is no guarantee that the relative grain-boundary cohesive strengths do not change with temperature. Thirdly, the temper-b...
{"title":"Grain-Boundary Segregation and Temper-Brittle Fracture in a Low-Alloy Steel","authors":"L. C. E. Geniets, J. F. Knottt","doi":"10.1179/030634572790445984","DOIUrl":"https://doi.org/10.1179/030634572790445984","url":null,"abstract":"AbstractConventional measurements of the degree of temperembrittlement suffered by a steel are made in terms of the shift of the notched-bar “fracture appearance” transition temperatures (FATT). Any fundamental explanation of temperembrittlement must be concerned with the lowering of grain-boundary cohesion by the segregation of impurity. elements to grain boundaries over a critical temperature range, typically 560–430° C. The use of transition shifts to estimate the kinetics of reduction of grain-boundary cohesion can be criticized on several counts. First, it is often the case that the unembrittled condition breaks by cleavage rather than by intergranular fracture at low temperatures, so that no measure of the unembrittled grain-boundary cohesion can be obtained. Secondly, even if both fractures are intergranular, the shift compares fracture events at different temperatures and there is no guarantee that the relative grain-boundary cohesive strengths do not change with temperature. Thirdly, the temper-b...","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"38 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":"115057527","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}
AbstractThe effect of variations in alloy composition, quench rate, and deformation on the formation of FPP (Frank partial precipitation) has been studied by means of hardness measurements and electron microscopy. Solute concentration is the most important factor controlling the maximum area of FPP. The numbers of precipitate particles increase with dislocation density but the number per unit length of dislocation is generally lower the higher is the dislocation density. The efficiency of nucleation by a dislocation is therefore not increased by the prior cold work and this is consistent with nucleation by climbed loops. The free-vacancy profile near grain boundaries is used to explain the FPP-free zone (PFZ) width, and this is controlled by the rate of precipitation. Silicon additions accelerate the nucleation of NbC and promote FPP formation.
{"title":"Factors Affecting the Precipitation of NbC on Frank Partial Dislocations in Fe–Ni–16% Cr Austenitic Steels","authors":"J. Silcock, K. W. Sidding, T. Fry","doi":"10.1179/MSC.1970.4.1.29","DOIUrl":"https://doi.org/10.1179/MSC.1970.4.1.29","url":null,"abstract":"AbstractThe effect of variations in alloy composition, quench rate, and deformation on the formation of FPP (Frank partial precipitation) has been studied by means of hardness measurements and electron microscopy. Solute concentration is the most important factor controlling the maximum area of FPP. The numbers of precipitate particles increase with dislocation density but the number per unit length of dislocation is generally lower the higher is the dislocation density. The efficiency of nucleation by a dislocation is therefore not increased by the prior cold work and this is consistent with nucleation by climbed loops. The free-vacancy profile near grain boundaries is used to explain the FPP-free zone (PFZ) width, and this is controlled by the rate of precipitation. Silicon additions accelerate the nucleation of NbC and promote FPP formation.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"14 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":"115058111","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}
AbstractReplicas have been examined both from the fracture surfaces and from polished sections of creep specimens of pure iron and copper, to determine the shape of grain-boundary cavities. From the observations a mechanism is proposed whereby combined grain-boundary sliding and grain deformation gives rise to cavity growth.
{"title":"Strain-Induced Cavity Development during Creep","authors":"P. W. Davies, K. R. Williams","doi":"10.1179/MSC.1969.3.1.48","DOIUrl":"https://doi.org/10.1179/MSC.1969.3.1.48","url":null,"abstract":"AbstractReplicas have been examined both from the fracture surfaces and from polished sections of creep specimens of pure iron and copper, to determine the shape of grain-boundary cavities. From the observations a mechanism is proposed whereby combined grain-boundary sliding and grain deformation gives rise to cavity growth.","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":"114693620","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: 10.1179/030634568790443288
S. R. Anthony, J. Congleton
Abstract The phenomenon of crack branching in metals is discussed in terms of KB, the elastic stress intensity at the crack tip when crack branching occurs. It is shown that KB measurements may be useful in determining the fracture toughness of brittle metals.
{"title":"Crack Branching in Strong Metals","authors":"S. R. Anthony, J. Congleton","doi":"10.1179/030634568790443288","DOIUrl":"https://doi.org/10.1179/030634568790443288","url":null,"abstract":"Abstract The phenomenon of crack branching in metals is discussed in terms of KB, the elastic stress intensity at the crack tip when crack branching occurs. It is shown that KB measurements may be useful in determining the fracture toughness of brittle metals.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"76 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":"114699496","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}
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