Pub Date : 1973-09-01DOI: 10.1179/030634573790445406
J. Evetts, P. J. Martin
AbstractSuperconductors have already found important application in magnets for research and in various types of equipment employed in high-energy physics. The extent to which they will be more generally used in the construction of generators, motors, and cables is still uncertain; probably the most important application in the near future (say 10–15 years) lies in the generation and distribution of electrical power, while in the longer term plasma containment for controlled thermonuclear fusion is possibly the most important application.
{"title":"Superconducting Materials Research","authors":"J. Evetts, P. J. Martin","doi":"10.1179/030634573790445406","DOIUrl":"https://doi.org/10.1179/030634573790445406","url":null,"abstract":"AbstractSuperconductors have already found important application in magnets for research and in various types of equipment employed in high-energy physics. The extent to which they will be more generally used in the construction of generators, motors, and cables is still uncertain; probably the most important application in the near future (say 10–15 years) lies in the generation and distribution of electrical power, while in the longer term plasma containment for controlled thermonuclear fusion is possibly the most important application.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1973-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122338660","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 : 1971-01-01DOI: 10.1179/030634571790439766
G. Beitel, C. Bowles
Abstract Polycrystal1ine 1100 and high-purity single-crystal aluminium samples were anodized to give oxide thicknesses between 200 and 1500 A, then subjected to low-cycle fatigue in high-humidity and vacuum environments. An ultrasonic method was used to identify crack initiation. Fatigue in a vacuum produces oxide cracks that are wider and fewer in number and results in an increase in fatigue life. Although the mode of fracture of both oxide and matrix is strongly dependent upon oxide thickness, it was found that neither the cycles to crack initiation nor the total fatigue lives were dependent upon oxide thickness.
{"title":"Influence of Anodic Layers on Fatigue-Crack Initiation in Aluminium","authors":"G. Beitel, C. Bowles","doi":"10.1179/030634571790439766","DOIUrl":"https://doi.org/10.1179/030634571790439766","url":null,"abstract":"Abstract Polycrystal1ine 1100 and high-purity single-crystal aluminium samples were anodized to give oxide thicknesses between 200 and 1500 A, then subjected to low-cycle fatigue in high-humidity and vacuum environments. An ultrasonic method was used to identify crack initiation. Fatigue in a vacuum produces oxide cracks that are wider and fewer in number and results in an increase in fatigue life. Although the mode of fracture of both oxide and matrix is strongly dependent upon oxide thickness, it was found that neither the cycles to crack initiation nor the total fatigue lives were dependent upon oxide thickness.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133326466","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: 10.1179/030634572790445777
E. Pink, R. Arsenault
AbstractThe thermal component, τ*, of the macroyield stress has been investigated for vanadium with 0.75, 1.6, 4, and 20 wt.-% titanium. The 4 wt.-% alloy showed a significant weakening effect below 100K. The temperature-dependence of the strain-rate-sensitivity for the alloys is discontinuous and indicates two different deformation mechanisms. At high temperatures a mechanism is operative that has a high H 0 value, i.e. 1.5eV. It is probably a distortion mechanism controlled by titanium atoms in clumps. At low temperatures the double-kink mechanism is rate-controlling. The titanium clumps can aid in the formation of double kinks by producing a torque on the screw dislocation. This torque reduces the τ* necessary for the formation of a double link, and therefore, “alloy weakening” is observed. The results strongly indicate that in relatively pure vanadium (< 50 at.-ppm) the impurity interstitials are not affecting τ*.
{"title":"Solid-Solution Strengthening and Weakening of Vanadium–Titanium Alloys","authors":"E. Pink, R. Arsenault","doi":"10.1179/030634572790445777","DOIUrl":"https://doi.org/10.1179/030634572790445777","url":null,"abstract":"AbstractThe thermal component, τ*, of the macroyield stress has been investigated for vanadium with 0.75, 1.6, 4, and 20 wt.-% titanium. The 4 wt.-% alloy showed a significant weakening effect below 100K. The temperature-dependence of the strain-rate-sensitivity for the alloys is discontinuous and indicates two different deformation mechanisms. At high temperatures a mechanism is operative that has a high H 0 value, i.e. 1.5eV. It is probably a distortion mechanism controlled by titanium atoms in clumps. At low temperatures the double-kink mechanism is rate-controlling. The titanium clumps can aid in the formation of double kinks by producing a torque on the screw dislocation. This torque reduces the τ* necessary for the formation of a double link, and therefore, “alloy weakening” is observed. The results strongly indicate that in relatively pure vanadium (< 50 at.-ppm) the impurity interstitials are not affecting τ*.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"18 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":"114657945","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: 10.1179/030634568790443215
M. Speight
AbstractThe rate of growth is derived of a fixed number of gas bubbles in a supersaturated solid, where therate-controlling process is the diffusion and not the assimilation of gas atoms at the bubble surface. Two expressions are obtained, corresponding to the perfect and non-perfect behaviour of the gas according to the pressure at which it is contained in the bubbles. In each case an abundant supply of thermal vacancies, which sustain equilibrium between the gas pressure and surface-tension restraint of the bubble, is taken to be available throughout the growth process. The necessary criterion that must be satisfied for this assumption to be valid is deduced.
{"title":"An Analysis of Bubble Growth in Materials Supersaturated with Inert Gas","authors":"M. Speight","doi":"10.1179/030634568790443215","DOIUrl":"https://doi.org/10.1179/030634568790443215","url":null,"abstract":"AbstractThe rate of growth is derived of a fixed number of gas bubbles in a supersaturated solid, where therate-controlling process is the diffusion and not the assimilation of gas atoms at the bubble surface. Two expressions are obtained, corresponding to the perfect and non-perfect behaviour of the gas according to the pressure at which it is contained in the bubbles. In each case an abundant supply of thermal vacancies, which sustain equilibrium between the gas pressure and surface-tension restraint of the bubble, is taken to be available throughout the growth process. The necessary criterion that must be satisfied for this assumption to be valid is deduced.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"1 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":"121819367","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: 10.1179/030634571790439702
C. P. Cutler, J. W. Edington
Abstract Texture measurements and metallographic studies have been made at various strains in material deformed with initial values of strain-rate sensitivity (m) = 0.2, 0.3, and 0.7. Texture becomes more random with increasing strain in both phases, independent of the value of m. Curved. grain boundaries and grain growth are produced by deformation and scratch-offset studies demonstrate that boundary sliding is occurring. The texture measurements are discussed in terms of the sliding process itself and possible associated accommodation mechanisms, both of which lead to grain rotation and a slow reduction in texture with increasing strain.
{"title":"Textures in the Superplastically Deformed Tin-Lead Eutectic Alloy","authors":"C. P. Cutler, J. W. Edington","doi":"10.1179/030634571790439702","DOIUrl":"https://doi.org/10.1179/030634571790439702","url":null,"abstract":"Abstract Texture measurements and metallographic studies have been made at various strains in material deformed with initial values of strain-rate sensitivity (m) = 0.2, 0.3, and 0.7. Texture becomes more random with increasing strain in both phases, independent of the value of m. Curved. grain boundaries and grain growth are produced by deformation and scratch-offset studies demonstrate that boundary sliding is occurring. The texture measurements are discussed in terms of the sliding process itself and possible associated accommodation mechanisms, both of which lead to grain rotation and a slow reduction in texture with increasing strain.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"65 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":"115753074","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: 10.1179/030634568790443279
D. Ashall, P. E. Evans
AbstractTheories of dispersion-phase-strengthening are briefly discussed and then critically examined in the light of experimental evidence obtained with nickel containing a fine dispersion of thoria. The results are in close agreement with Orowan's theory. The work-hardening theory of Fisher, Hart, and Pry, though in qualitative agreement with the experimental results, postulates the formation of concentric dislocation loops around particles of the dispersed phase. Transmission electron micrographs of the nickel-thoria indicate that the formation of prismatic loops near to particles is a more likely process, and this is borne out by analysis of the experimental results.
{"title":"Yielding and Work-Hardening in Ni-ThO2 Alloys","authors":"D. Ashall, P. E. Evans","doi":"10.1179/030634568790443279","DOIUrl":"https://doi.org/10.1179/030634568790443279","url":null,"abstract":"AbstractTheories of dispersion-phase-strengthening are briefly discussed and then critically examined in the light of experimental evidence obtained with nickel containing a fine dispersion of thoria. The results are in close agreement with Orowan's theory. The work-hardening theory of Fisher, Hart, and Pry, though in qualitative agreement with the experimental results, postulates the formation of concentric dislocation loops around particles of the dispersed phase. Transmission electron micrographs of the nickel-thoria indicate that the formation of prismatic loops near to particles is a more likely process, and this is borne out by analysis of the experimental results.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"57 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":"116906160","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 Schmid Factors for the twelve {112}〈111〉 twinning systems in body-centred cubic crystals have been calculated. From these, the orientations that will give a crystal the greatest probability of twinning on one system only are derived. These orientations are [1.189, 2, 2] for crystals tested in compression and [1, 1.667, 2] for crystals tested in tension. As the maximum Schmid Factor for {l01}〈111〉 slip is high and the maximum Schmid Factor for twinning in tension is low at [1, 1.667, 2], it is concluded that testing in compression at [1.189, 2,2] will give the greatest probability of producing one, and only one, family of twins.
{"title":"A Discussion of Schmid Factors for Twinning in B.C.C. Crystals","authors":"D. Williams","doi":"10.1179/MSC.1967.1.1.94","DOIUrl":"https://doi.org/10.1179/MSC.1967.1.1.94","url":null,"abstract":"AbstractThe Schmid Factors for the twelve {112}〈111〉 twinning systems in body-centred cubic crystals have been calculated. From these, the orientations that will give a crystal the greatest probability of twinning on one system only are derived. These orientations are [1.189, 2, 2] for crystals tested in compression and [1, 1.667, 2] for crystals tested in tension. As the maximum Schmid Factor for {l01}〈111〉 slip is high and the maximum Schmid Factor for twinning in tension is low at [1, 1.667, 2], it is concluded that testing in compression at [1.189, 2,2] will give the greatest probability of producing one, and only one, family of twins.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"40 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":"121266757","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}
AbstractElectron-microscope examination of a pure iron and two commercial low-carbon steels has enabled the driving force for recrystallization to be evaluated as a function of orientation. The two classical approaches to annealing-texture development, the oriented-growth and the oriented-nucleation theories, have been compared on the basis of the results obtained and it is concluded that in the early stages of recrystallization oriented nucleation predominates in the selection of orientations.
{"title":"Oriented Nucleation in the Formation of Annealing Textures in Iron","authors":"I. Dillamore, C. J. Smith, T. W. Watson","doi":"10.1179/MSC.1967.1.1.49","DOIUrl":"https://doi.org/10.1179/MSC.1967.1.1.49","url":null,"abstract":"AbstractElectron-microscope examination of a pure iron and two commercial low-carbon steels has enabled the driving force for recrystallization to be evaluated as a function of orientation. The two classical approaches to annealing-texture development, the oriented-growth and the oriented-nucleation theories, have been compared on the basis of the results obtained and it is concluded that in the early stages of recrystallization oriented nucleation predominates in the selection of orientations.","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":"127292494","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.1970.4.1.144
D. Mclean
AbstractIn polycrystals, geometrical reasoning shows that grain-boundary sliding and diffusion can combine to give nearly unlimited deformation (as observed in superplastic alloys), but the genuine sliding cannot contribute much more than half the total deformation, although measured offsets may be erroneously large.
{"title":"Grain-Boundary Sliding: A Finite but Unbounded Limit","authors":"D. Mclean","doi":"10.1179/MSC.1970.4.1.144","DOIUrl":"https://doi.org/10.1179/MSC.1970.4.1.144","url":null,"abstract":"AbstractIn polycrystals, geometrical reasoning shows that grain-boundary sliding and diffusion can combine to give nearly unlimited deformation (as observed in superplastic alloys), but the genuine sliding cannot contribute much more than half the total deformation, although measured offsets may be erroneously large.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"8 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":"125409261","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}
AbstractHigh-temperature creep studies have been conducted on “recrystallized” nickel-tho ria alloys which contained various ThO2 particle sizes (220-550 A dia.) and volume fractions (0.01-0.045). Creep results, together with structural studies employing electron microscopy, indicate that the rate-controlling creep process is the climb of edge dislocations over ThO2 particles. Calculations predict that the steady-state creep rate, έ s , is related to particle size and spacing by e s ∝ d2/r v , where d is the mean planar centre-to-centre particle spacing, and r v is the average particle radius. This relation is in accord with experimental observations.
{"title":"Steady-State Creep of Dispersion-Strengthened Nickel","authors":"A. Clauer, B. A. Wilcox","doi":"10.1179/MSC.1967.1.1.86","DOIUrl":"https://doi.org/10.1179/MSC.1967.1.1.86","url":null,"abstract":"AbstractHigh-temperature creep studies have been conducted on “recrystallized” nickel-tho ria alloys which contained various ThO2 particle sizes (220-550 A dia.) and volume fractions (0.01-0.045). Creep results, together with structural studies employing electron microscopy, indicate that the rate-controlling creep process is the climb of edge dislocations over ThO2 particles. Calculations predict that the steady-state creep rate, έ s , is related to particle size and spacing by e s ∝ d2/r v , where d is the mean planar centre-to-centre particle spacing, and r v is the average particle radius. This relation is in accord with experimental observations.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"11 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":"115537643","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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