Pub Date : 1900-01-01DOI: 10.1179/MSC.1967.1.1.171
Y. Ishida, D. Mclean
AbstractGrain-boundary dislocations may play a crucial role in creep fracture.Despite initial successes, the existing diffusion theory regarding the formation and growth of cavities in creep is now encountering serious difficulties in its attempt to deal with the rates of these processes. For instance, the measured growth rates of cavities have been found to agree with those calculated from the diffusion theory in the case of a pure metal; in the case of a strong alloy the calculated rate would not alter much, since diffusion coefficients are not changed substantially by alloying, but the actual rate is greatly reduced in something like the same ratio as the creep rate. Theory and experiment are then far apart. Another instance is that in an early calculation in which the competition between the opening of a cavity by grain-boundary sliding and its closure by sintering was considered, it was concluded that the latter did not predominate over the former, but correction of an error reverses this conclusion....
{"title":"The Formation and Growth of Cavities in Creep","authors":"Y. Ishida, D. Mclean","doi":"10.1179/MSC.1967.1.1.171","DOIUrl":"https://doi.org/10.1179/MSC.1967.1.1.171","url":null,"abstract":"AbstractGrain-boundary dislocations may play a crucial role in creep fracture.Despite initial successes, the existing diffusion theory regarding the formation and growth of cavities in creep is now encountering serious difficulties in its attempt to deal with the rates of these processes. For instance, the measured growth rates of cavities have been found to agree with those calculated from the diffusion theory in the case of a pure metal; in the case of a strong alloy the calculated rate would not alter much, since diffusion coefficients are not changed substantially by alloying, but the actual rate is greatly reduced in something like the same ratio as the creep rate. Theory and experiment are then far apart. Another instance is that in an early calculation in which the competition between the opening of a cavity by grain-boundary sliding and its closure by sintering was considered, it was concluded that the latter did not predominate over the former, but correction of an error reverses this conclusion....","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"416 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":"123549211","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.1969.3.1.234
D. Woodford
Abstract Stepped creep bars providing four different stresses on each specimen have been tested at 525° C for up to 850 h. Density changes in each section following creep are used to determine the effect of the test variables on V, the total void volume/unit weight. It is shown that the density changes are described by the relationship V = 1·52 × 10−38 ɛ t σ7·5, where ɛ is the strain, t the time in h, and σ the initial stress in lbf/in2. This equation is valid to the point of rupture and calculated rupture times are in good agreement with actual values. However, since a knowledge of the value of V at rupture is required for such a prediction, it is doubtful whether the approach will be suitable for purposes of extrapolation. It is demonstrated that some of the assumptions made in the past regarding cavitation damage are untenable. In particular, the amount of damage at failure or at any stage of the creep curve is dependent on the test conditions. There is no reason to suspect that the development of cavi...
在525°C下对每个试样提供四种不同应力的阶梯蠕变棒进行了长达850小时的测试。使用蠕变后每个部分的密度变化来确定测试变量对V(总空隙体积/单位重量)的影响。结果表明，密度变化的关系式为V = 1·52 × 10−38 μ t σ 7.5，其中，μ为应变，t为时间，σ为初始应力，单位为lbf/in2。该方程对破裂点有效，计算的破裂时间与实际值吻合较好。然而，由于这种预测需要知道破裂时的V值，因此这种方法是否适用于外推是值得怀疑的。论证了过去关于空化损害的一些假设是站不住脚的。特别是，破坏时或在蠕变曲线的任何阶段的损伤量取决于试验条件。没有理由怀疑cavi的发展…
{"title":"Density Changes during Creep in Nickel","authors":"D. Woodford","doi":"10.1179/MSC.1969.3.1.234","DOIUrl":"https://doi.org/10.1179/MSC.1969.3.1.234","url":null,"abstract":"Abstract Stepped creep bars providing four different stresses on each specimen have been tested at 525° C for up to 850 h. Density changes in each section following creep are used to determine the effect of the test variables on V, the total void volume/unit weight. It is shown that the density changes are described by the relationship V = 1·52 × 10−38 ɛ t σ7·5, where ɛ is the strain, t the time in h, and σ the initial stress in lbf/in2. This equation is valid to the point of rupture and calculated rupture times are in good agreement with actual values. However, since a knowledge of the value of V at rupture is required for such a prediction, it is doubtful whether the approach will be suitable for purposes of extrapolation. It is demonstrated that some of the assumptions made in the past regarding cavitation damage are untenable. In particular, the amount of damage at failure or at any stage of the creep curve is dependent on the test conditions. There is no reason to suspect that the development of cavi...","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"36 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":"116814192","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: 10.1179/030634573790445352
R. A. Connell, D. B. Downie
AbstractA calorimetric study of aluminium–zinc alloys containing up to 60 at.-% Zn has yielded values of the enthalpy of formation that compare well with those of previous work by Wittig and Schoffl (Z. Metallkunde, 1960, 51, 700). Trends in composition and temperature coefficients are also in good agreement. It is suggested that values of the enthalpy of mixing in both studies are more consistent with a previously proposed modification to the phase diagram than are those obtained from emf studies. Excess entropies of mixing have been calculated by combining the enthalpies obtained by calorimetry with the excess free energies from the emf measurements.
{"title":"The Enthalpies of Formation of α-Phase Al-Zn Alloys","authors":"R. A. Connell, D. B. Downie","doi":"10.1179/030634573790445352","DOIUrl":"https://doi.org/10.1179/030634573790445352","url":null,"abstract":"AbstractA calorimetric study of aluminium–zinc alloys containing up to 60 at.-% Zn has yielded values of the enthalpy of formation that compare well with those of previous work by Wittig and Schoffl (Z. Metallkunde, 1960, 51, 700). Trends in composition and temperature coefficients are also in good agreement. It is suggested that values of the enthalpy of mixing in both studies are more consistent with a previously proposed modification to the phase diagram than are those obtained from emf studies. Excess entropies of mixing have been calculated by combining the enthalpies obtained by calorimetry with the excess free energies from the emf measurements.","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":"117182755","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: 10.1179/030634568790443558
E. Almond, J. Embury
AbstractThe mechanical properties of a low-carbon steel and a Swedish iron have been examined over a range of temperatures from − 196 to 150°C by means of an instrumented impact test. Load vs. temperature curves exhibit similar features to curves obtained from notch bend tests. The effects of specimen geometry and microstructure on the fracture stress have been studied and the results are discussed in terms of a critical tensile stress for slip-initiated cleavage fracture.
{"title":"Instrumented Impact Testing of Low-Carbon Steels","authors":"E. Almond, J. Embury","doi":"10.1179/030634568790443558","DOIUrl":"https://doi.org/10.1179/030634568790443558","url":null,"abstract":"AbstractThe mechanical properties of a low-carbon steel and a Swedish iron have been examined over a range of temperatures from − 196 to 150°C by means of an instrumented impact test. Load vs. temperature curves exhibit similar features to curves obtained from notch bend tests. The effects of specimen geometry and microstructure on the fracture stress have been studied and the results are discussed in terms of a critical tensile stress for slip-initiated cleavage fracture.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"13 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":"123926788","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: 10.1179/030634573790445316
P. J. Turner, J. Papazian
AbstractSmall-scale analyses have been made by the field-ion atom-probe technique on high-purity iron containing 0.05 at.-% carbon, on an Fe-4%Mo-0.2%C steel, and an Fe-5%Mo-0.1%N steel. Analysis of the iron–carbon alloy at 50 K showed the presence of iron only (together with hydrogen as a surface impurity) and background levels for all other elements of less than one part per thousand. Determinations made near a grain boundary in the same. material showed a carbon concentration of 0.4 at.-%, indicating segregation but at a level well below monolayer coverage. Analysis of precipitates in the iron–molybdenum–carbon alloy gave a composition of Mo2C, in agreement with previous investigations. Analysis of precipitates in the iron–molybdenum–nitrogen alloy gave a composition of Mo2N with 10% of the molybdenum replaced by iron. These latter two results indicate that the response of the instrument to the various ions is not significantly biased and that the unexpectedly low number of carbon signals from the grai...
{"title":"Some Applications of Field-Ion Atom-Probe Analysis to Iron and Steels","authors":"P. J. Turner, J. Papazian","doi":"10.1179/030634573790445316","DOIUrl":"https://doi.org/10.1179/030634573790445316","url":null,"abstract":"AbstractSmall-scale analyses have been made by the field-ion atom-probe technique on high-purity iron containing 0.05 at.-% carbon, on an Fe-4%Mo-0.2%C steel, and an Fe-5%Mo-0.1%N steel. Analysis of the iron–carbon alloy at 50 K showed the presence of iron only (together with hydrogen as a surface impurity) and background levels for all other elements of less than one part per thousand. Determinations made near a grain boundary in the same. material showed a carbon concentration of 0.4 at.-%, indicating segregation but at a level well below monolayer coverage. Analysis of precipitates in the iron–molybdenum–carbon alloy gave a composition of Mo2C, in agreement with previous investigations. Analysis of precipitates in the iron–molybdenum–nitrogen alloy gave a composition of Mo2N with 10% of the molybdenum replaced by iron. These latter two results indicate that the response of the instrument to the various ions is not significantly biased and that the unexpectedly low number of carbon signals from the grai...","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"12 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":"126197552","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.1967.1.1.145
A. Saarinen, H. M. Miekk-oja
AbstractAttention is directed to the extension of a dislocation by the acting stress in metals having a low stacking-fault energy. It is shown that stress-induced stacking faults impede the movement of dislocations on intersecting slip planes, causing overshoot in copper-aluminium single crystals when tested in tension.
{"title":"Stress-Induced Stacking Faults and Their Interference with Slip on Intersecting Planes in Copper-Aluminium Alloys","authors":"A. Saarinen, H. M. Miekk-oja","doi":"10.1179/MSC.1967.1.1.145","DOIUrl":"https://doi.org/10.1179/MSC.1967.1.1.145","url":null,"abstract":"AbstractAttention is directed to the extension of a dislocation by the acting stress in metals having a low stacking-fault energy. It is shown that stress-induced stacking faults impede the movement of dislocations on intersecting slip planes, causing overshoot in copper-aluminium single crystals when tested in tension.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"4 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":"129768733","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: 10.1179/030634573790445640
J. P. Sadocha, H. W. Kerr
AbstractThe growth kinetics of lead-rich grains in partially molten Pb-Sb-Sn and Pb-Sb-Sn-As alloys has been studied. In alloys containing one solid phase, the average grain size d is related to the time t by the equation d3 – d 13 = K 1(t – t 1), as predicted by a model which assumes that liquid diffusion is the ratecontrolling process. The measured activation energies were larger than those usually found for self-diffusion in liquids. The presence of a second solid phase tended to limit the grain growth of the lead-rich phase increasing the time exponent from 3.0. An increased fraction or finer distribution of the second phase restricted the grain sizes to a greater extent. For a constant distribution and quantity of the second phase the kinetics increased and then decreased with increasing fractions of liquid due to an increased percentage of antimony.
摘要研究了部分熔融Pb-Sb-Sn和Pb-Sb-Sn- as合金中富铅晶粒的生长动力学。在含一个固相的合金中，平均晶粒尺寸d与时间t的关系为公式d3 - d 13 = k1 (t - t1)，这是一个假设液体扩散是速率控制过程的模型所预测的。测量的活化能比通常在液体中发现的自扩散活化能要大。第二固相的存在往往会限制富铅相的晶粒长大，时间指数从3.0开始增加。增加的分数或更细的第二相分布在更大程度上限制了晶粒尺寸。对于第二相的恒定分布和数量，动力学随着液体分数的增加而增加，然后由于锑的百分比增加而降低。
{"title":"Grain-Ripening of the Lead-Rich Phase in Partially Molten Pb-Sb-Sn and Pb-Sb-Sn-As Solders","authors":"J. P. Sadocha, H. W. Kerr","doi":"10.1179/030634573790445640","DOIUrl":"https://doi.org/10.1179/030634573790445640","url":null,"abstract":"AbstractThe growth kinetics of lead-rich grains in partially molten Pb-Sb-Sn and Pb-Sb-Sn-As alloys has been studied. In alloys containing one solid phase, the average grain size d is related to the time t by the equation d3 – d 13 = K 1(t – t 1), as predicted by a model which assumes that liquid diffusion is the ratecontrolling process. The measured activation energies were larger than those usually found for self-diffusion in liquids. The presence of a second solid phase tended to limit the grain growth of the lead-rich phase increasing the time exponent from 3.0. An increased fraction or finer distribution of the second phase restricted the grain sizes to a greater extent. For a constant distribution and quantity of the second phase the kinetics increased and then decreased with increasing fractions of liquid due to an increased percentage of antimony.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"28 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":"129900032","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: 10.1179/030634573790445424
K. Melton, J. W. Edington
AbstractThe mechanical properties of extruded Zn-40wt.-%Al and Zn-50wt.-%Al alloys have been investigated and correlated with their microstructures as determined by transmission electron microscopy. The effect of composition on the superplastic properties is discussed and microstructural evidence has been obtained for slip deformation during superplastic flow of the Zn-40wt.-% Al alloy.
{"title":"Superplasticity in Extruded Zn-40wt.-%Al and Zn-50wt.-% Al Alloys","authors":"K. Melton, J. W. Edington","doi":"10.1179/030634573790445424","DOIUrl":"https://doi.org/10.1179/030634573790445424","url":null,"abstract":"AbstractThe mechanical properties of extruded Zn-40wt.-%Al and Zn-50wt.-%Al alloys have been investigated and correlated with their microstructures as determined by transmission electron microscopy. The effect of composition on the superplastic properties is discussed and microstructural evidence has been obtained for slip deformation during superplastic flow of the Zn-40wt.-% Al alloy.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"3 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":"128700900","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: 10.1179/030634572790446091
R. Lagneborg
AbstractBased upon previous treatments of the recovery-creep theory a model. has been formulated that takes into account the separation of the applied stress into an effective stress and an internal stress and the experimentally determined stress-dependence of the activation area. The model describes the time- and stress-dependence of the creep rate in the primary and the secondary stages. It is shown that the theory adequately simulates the experimental creep curves. The attainment of constant true and apparent activation energies, and of a constant exponent in the creep rate/stress power law, are interpreted as different consequences of the internal stress being approximately equal to the applied stress at low stresses and high temperatures. The physical significance of the apparent activation energy is discussed in terms of the model.
{"title":"A Modified Recovery-Creep Model and Its Evaluation","authors":"R. Lagneborg","doi":"10.1179/030634572790446091","DOIUrl":"https://doi.org/10.1179/030634572790446091","url":null,"abstract":"AbstractBased upon previous treatments of the recovery-creep theory a model. has been formulated that takes into account the separation of the applied stress into an effective stress and an internal stress and the experimentally determined stress-dependence of the activation area. The model describes the time- and stress-dependence of the creep rate in the primary and the secondary stages. It is shown that the theory adequately simulates the experimental creep curves. The attainment of constant true and apparent activation energies, and of a constant exponent in the creep rate/stress power law, are interpreted as different consequences of the internal stress being approximately equal to the applied stress at low stresses and high temperatures. The physical significance of the apparent activation energy is discussed in terms of the model.","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":"127515610","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 thermodynamic properties of iron-gold and cobalt-gold alloys have been measured between 750 and 1000° C by an e.m.f. method with ThO2–YO1.5 electrolytes. Results are given for activities, entropies, and heats of mixing across the complete range of composition and the phase diagrams published in Hansen's compilation (M. Hansen and K. Anderko, “Constitution of Binary Alloys”. 1958: New York and London (McGraw-Hill))are shown to be consistent with the thermodynamic results now obtained. It is concluded that the heat-of-mixing term is the dominant factor in defining the phase fields of the diagrams and a tentative model is proposed.
{"title":"A Thermodynamic Study of Solid Iron-Gold and Cobalt-Gold Alloys by the Use of Solid Oxide Electrolytes","authors":"A. Kubik, C. B. Alcock","doi":"10.1179/MSC.1967.1.1.19","DOIUrl":"https://doi.org/10.1179/MSC.1967.1.1.19","url":null,"abstract":"AbstractThe thermodynamic properties of iron-gold and cobalt-gold alloys have been measured between 750 and 1000° C by an e.m.f. method with ThO2–YO1.5 electrolytes. Results are given for activities, entropies, and heats of mixing across the complete range of composition and the phase diagrams published in Hansen's compilation (M. Hansen and K. Anderko, “Constitution of Binary Alloys”. 1958: New York and London (McGraw-Hill))are shown to be consistent with the thermodynamic results now obtained. It is concluded that the heat-of-mixing term is the dominant factor in defining the phase fields of the diagrams and a tentative model is proposed.","PeriodicalId":103313,"journal":{"name":"Metal Science Journal","volume":"6 7 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":"132145202","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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