Pub Date : 1900-01-01DOI: 10.1179/030634572790446037
T. Williams
AbstractThe boron autoradiography techniques, using optical and electron microscopy, developed at the Atomic Energy Research Establishment, Harwell, have been described in some detail in two publications by Hughes et al. The present paper illustrates the usefulness of the techniques in the study of the effects of boron on the properties of Type-316 stainless steel.
{"title":"The Segregation and Effects of Boron in an Austenitic Stainless Steel","authors":"T. Williams","doi":"10.1179/030634572790446037","DOIUrl":"https://doi.org/10.1179/030634572790446037","url":null,"abstract":"AbstractThe boron autoradiography techniques, using optical and electron microscopy, developed at the Atomic Energy Research Establishment, Harwell, have been described in some detail in two publications by Hughes et al. The present paper illustrates the usefulness of the techniques in the study of the effects of boron on the properties of Type-316 stainless steel.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"16 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":"123388784","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: 10.1179/030634572790445975
B. Noble, G. Thompson
Abstract T 1 precipitation has been studied by electron microscopy in aluminium alloys containing (wt.-%) Cu 3.5, Li 1.5 and Cu 2.5, Li 2.0. The T 1 phase forms as extremely thin hexagonal-shaped plates with a {111} habit plane and, depending on the degree of super-saturation, nucleates either at GP zones or at dissociated dislocations by a stacking-fault mechanism. The precipitate is bounded by 1/6 Shockley partial dislocations and growth of the phase occurs by separation of these partial dislocations.
摘要:用电镜研究了(wt.-%) Cu 3.5, Li 1.5和Cu 2.5, Li 2.0铝合金中的t1析出。t1相形成极薄的六边形板，具有{111}习惯面，并且根据过饱和程度，在GP带或通过堆叠-断层机制在解离位错处成核。析出相以1/6肖克利部分位错为界，这些部分位错的分离使相长大。
{"title":"T 1 (Al2CuLi) Precipitation in Aluminium–Copper–Lithium Alloys","authors":"B. Noble, G. Thompson","doi":"10.1179/030634572790445975","DOIUrl":"https://doi.org/10.1179/030634572790445975","url":null,"abstract":"Abstract T 1 precipitation has been studied by electron microscopy in aluminium alloys containing (wt.-%) Cu 3.5, Li 1.5 and Cu 2.5, Li 2.0. The T 1 phase forms as extremely thin hexagonal-shaped plates with a {111} habit plane and, depending on the degree of super-saturation, nucleates either at GP zones or at dissociated dislocations by a stacking-fault mechanism. The precipitate is bounded by 1/6 Shockley partial dislocations and growth of the phase occurs by separation of these partial dislocations.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"175 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":"123839740","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: 10.1179/030634573790445307
W. Yang, R. Dodd
Abstract The high- and intermediate-temperature creep properties of NiAl are quite sensitive to deviations from stoichiometry, although the creep always appears to be diffusion-controlled. The unusual dislocation micro-structures in Al-rich NiAl and the demonstrated influence of impurities in stoichiometric NiAl preclude a straightforward analysis of intrinsic rate-determining mechanisms.
{"title":"Steady-State Creep and Associated Microstructures in Stoichiometric and Non-Stoichiometric Polycrystalline NiAl","authors":"W. Yang, R. Dodd","doi":"10.1179/030634573790445307","DOIUrl":"https://doi.org/10.1179/030634573790445307","url":null,"abstract":"Abstract The high- and intermediate-temperature creep properties of NiAl are quite sensitive to deviations from stoichiometry, although the creep always appears to be diffusion-controlled. The unusual dislocation micro-structures in Al-rich NiAl and the demonstrated influence of impurities in stoichiometric NiAl preclude a straightforward analysis of intrinsic rate-determining mechanisms.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"41 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":"126138762","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.1970.4.1.222
H. B. Aaron, G. Kotler
AbstractThe effects of curvature on the dissolution kinetics of spherical precipitates is investigated. This is accomplished by using a modified Gibbs–Thompson equation to represent the composition in the matrix at the precipitate/matrix interface as a function of precipitate radius. In this way one can account for the increasing curvature of the dissolving precipitate. The range of physical parameters for which the effect of curvature may appreciably alter the kinetics of diffusion-controlled dissolution is discussed. The presence of curvature tends to speed up dissolution, being particularly important at long times (i.e., small precipitate sizes) and when the difference between the solute concentration at the precipitate/matrix interface (Cr I ) and in the depleted matrix (C M ) is small. It is shown, however, that curvature will, in general, not sensibly affect the dissolution kinetics even at long times unless the concentration difference (Cr I – C M ) is sufficiently small.
摘要研究了曲率对球形析出物溶解动力学的影响。这是通过使用改进的Gibbs-Thompson方程来实现的，该方程将析出物/基体界面处的基体成分表示为析出物半径的函数。这样就可以解释溶解沉淀物曲率的增加。讨论了曲率影响可能显著改变扩散控制溶解动力学的物理参数范围。曲率的存在倾向于加速溶解，这在时间长(即析出物尺寸小)和析出物/基体界面(Cr I)和耗尽基体(cm)的溶质浓度差很小的情况下尤为重要。然而，一般来说，曲率即使在很长时间内也不会明显影响溶解动力学，除非浓度差(Cr I - cm)足够小。
{"title":"The Effects of Curvature on the Dissolution Kinetics of Spherical Precipitates","authors":"H. B. Aaron, G. Kotler","doi":"10.1179/MSC.1970.4.1.222","DOIUrl":"https://doi.org/10.1179/MSC.1970.4.1.222","url":null,"abstract":"AbstractThe effects of curvature on the dissolution kinetics of spherical precipitates is investigated. This is accomplished by using a modified Gibbs–Thompson equation to represent the composition in the matrix at the precipitate/matrix interface as a function of precipitate radius. In this way one can account for the increasing curvature of the dissolving precipitate. The range of physical parameters for which the effect of curvature may appreciably alter the kinetics of diffusion-controlled dissolution is discussed. The presence of curvature tends to speed up dissolution, being particularly important at long times (i.e., small precipitate sizes) and when the difference between the solute concentration at the precipitate/matrix interface (Cr I ) and in the depleted matrix (C M ) is small. It is shown, however, that curvature will, in general, not sensibly affect the dissolution kinetics even at long times unless the concentration difference (Cr I – C M ) is sufficiently small.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"127 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":"128901597","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.1967.1.1.104
R. Wasilewski, S. R. Butler, J. Hanlon
Abstract The structural transformation of the CsCl-type compound TiNi has been investigated by X-ray-diffraction, calorimetric, and metallographic methods. The transition is a first-order one, with a latent heat of 370 ± 20 cal/g-atom. It occurs rapidly and with small hysteresis in bulk material, the transition temperature varying with composition within the range 48–52 at.-%nickel, and its martensitic character was confirmed by metallographic and electron-microscope observations. The martensite (low-temperature) structure is probably of low symmetry. There is some evidence that different transition products are formed on either side of the stoichiometry. Oxygen level significantly affects the transition behaviour.
{"title":"On the Martensitic Transformation in TiNi","authors":"R. Wasilewski, S. R. Butler, J. Hanlon","doi":"10.1179/MSC.1967.1.1.104","DOIUrl":"https://doi.org/10.1179/MSC.1967.1.1.104","url":null,"abstract":"Abstract The structural transformation of the CsCl-type compound TiNi has been investigated by X-ray-diffraction, calorimetric, and metallographic methods. The transition is a first-order one, with a latent heat of 370 ± 20 cal/g-atom. It occurs rapidly and with small hysteresis in bulk material, the transition temperature varying with composition within the range 48–52 at.-%nickel, and its martensitic character was confirmed by metallographic and electron-microscope observations. The martensite (low-temperature) structure is probably of low symmetry. There is some evidence that different transition products are formed on either side of the stoichiometry. Oxygen level significantly affects the transition behaviour.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"26 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":"121924960","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}
AbstractTensile tests and transmission electron microscopy have been used to investigate the relationship between mechanical properties and microstructure in three plain carbon steels shock-loaded to peak pressures between 100 and 250 kilobars. The most dramatic change in structures and properties occurs at pressures in excess of that required to induce the phase transformation α → ɛ → α. The value of this pressure depends on the original microstructure of the steel, so that an annealed low-carbon steel shows considerable transformation at 150 kilobars, while a normalized 0.99% C steel does not transform until the peak pressure exceeds 200 kilobars. Below the transformation pressure the low-carbon steel is strengthened by shock-loading, while this does not occur in the two high-carbon steels.
{"title":"The Structure and Mechanical Properties of Shock-Loaded Steels","authors":"H. Bowden, P. Kelly","doi":"10.1179/MSC.1967.1.1.75","DOIUrl":"https://doi.org/10.1179/MSC.1967.1.1.75","url":null,"abstract":"AbstractTensile tests and transmission electron microscopy have been used to investigate the relationship between mechanical properties and microstructure in three plain carbon steels shock-loaded to peak pressures between 100 and 250 kilobars. The most dramatic change in structures and properties occurs at pressures in excess of that required to induce the phase transformation α → ɛ → α. The value of this pressure depends on the original microstructure of the steel, so that an annealed low-carbon steel shows considerable transformation at 150 kilobars, while a normalized 0.99% C steel does not transform until the peak pressure exceeds 200 kilobars. Below the transformation pressure the low-carbon steel is strengthened by shock-loading, while this does not occur in the two high-carbon steels.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"29 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":"122500531","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: 10.1179/030634572790446028
C. M. Wayman, K. Shimizu
AbstractThe shape memory effect, by which a material, apparently plastically deformed, reverts to its original shape upon heating to some higher temperature, has been reviewed and discussed from the point of view of the crystallography of martensitic transformations. Considering the general characteristics of martensitic materials that exhibit the shape memory behaviour, some phenomena peculiar to the prototype NiTi alloy are shown to have no direct relation to the shape memory. It is concluded that the shape memory effect can be universally correlated with a martensitic transformation that is thermoelastic in nature, the thermoelasticity being attributed to ordering in the parent and martensitic phases.Prerequisites for the shape memory behaviour are suggested to be: (1) that the martensitic transformation is thermoelastic; (2) that the parent and martensitic phases are ordered; and (3) that the martensite is internally twinned. The low-temperature deformation process is discussed with reference to the l...
{"title":"The Shape Memory (‘Marmem’) Effect in Alloys","authors":"C. M. Wayman, K. Shimizu","doi":"10.1179/030634572790446028","DOIUrl":"https://doi.org/10.1179/030634572790446028","url":null,"abstract":"AbstractThe shape memory effect, by which a material, apparently plastically deformed, reverts to its original shape upon heating to some higher temperature, has been reviewed and discussed from the point of view of the crystallography of martensitic transformations. Considering the general characteristics of martensitic materials that exhibit the shape memory behaviour, some phenomena peculiar to the prototype NiTi alloy are shown to have no direct relation to the shape memory. It is concluded that the shape memory effect can be universally correlated with a martensitic transformation that is thermoelastic in nature, the thermoelasticity being attributed to ordering in the parent and martensitic phases.Prerequisites for the shape memory behaviour are suggested to be: (1) that the martensitic transformation is thermoelastic; (2) that the parent and martensitic phases are ordered; and (3) that the martensite is internally twinned. The low-temperature deformation process is discussed with reference to the l...","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":"122601345","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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