Pub Date : 1984-08-01DOI: 10.1179/030634584790419863
Y. Minamino, T. Yamane, S. Ueno, M. Koizumi, N. Ogawa, M. Shimada
Abstract The react diffusion under pressures of 0–3 GPa has been investigated in the Al-Ag system at temperatures of 729–873 K. The only phase appearing in the diffusion zone under pressures of 0–3 GPa is ς phase. The rate constants of phase growth and the interdiffusion coefficients decrease with increasing pressure. The activation volumes of interdiffusion and phase growth of ς phase are determined to be 7.9 × 10−6 and 7.0 × 10−6 m3 mol−1 respectively. These values of activation volume indicate that phase growth is controlled by diffusion occurring by the monovacancy mechanism.
{"title":"Effect of high pressure on react diffusion in Al-Ag system","authors":"Y. Minamino, T. Yamane, S. Ueno, M. Koizumi, N. Ogawa, M. Shimada","doi":"10.1179/030634584790419863","DOIUrl":"https://doi.org/10.1179/030634584790419863","url":null,"abstract":"Abstract The react diffusion under pressures of 0–3 GPa has been investigated in the Al-Ag system at temperatures of 729–873 K. The only phase appearing in the diffusion zone under pressures of 0–3 GPa is ς phase. The rate constants of phase growth and the interdiffusion coefficients decrease with increasing pressure. The activation volumes of interdiffusion and phase growth of ς phase are determined to be 7.9 × 10−6 and 7.0 × 10−6 m3 mol−1 respectively. These values of activation volume indicate that phase growth is controlled by diffusion occurring by the monovacancy mechanism.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"79 1","pages":"419-426"},"PeriodicalIF":0.0,"publicationDate":"1984-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80881985","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 : 1984-07-01DOI: 10.1179/030634584790419881
C. W. Brown, J. King, M. Hicks
The use of engineering materials in critical applications necessitates the accurate prediction of component lifetime for inspection and renewal purposes. In fatigue limited situations, it is necessary to be able to predict the growth rates of cracks from initiation at a defect through to final fracture. To this end, fatigue crack growth data are presented for different microstructures of typical nickel base superalloys used in gas turbine engines. Crack growth behaviour throughout the life history of the crack, i.e. from the short crack through to the long crack propagation regime, is described for each microstructural condition and discussed in terms of current theories of fatigue crack propagation.
{"title":"Effects of microstructure on long and short crack growth in nickel base superalloys","authors":"C. W. Brown, J. King, M. Hicks","doi":"10.1179/030634584790419881","DOIUrl":"https://doi.org/10.1179/030634584790419881","url":null,"abstract":"The use of engineering materials in critical applications necessitates the accurate prediction of component lifetime for inspection and renewal purposes. In fatigue limited situations, it is necessary to be able to predict the growth rates of cracks from initiation at a defect through to final fracture. To this end, fatigue crack growth data are presented for different microstructures of typical nickel base superalloys used in gas turbine engines. Crack growth behaviour throughout the life history of the crack, i.e. from the short crack through to the long crack propagation regime, is described for each microstructural condition and discussed in terms of current theories of fatigue crack propagation.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"45 1","pages":"374-380"},"PeriodicalIF":0.0,"publicationDate":"1984-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79424758","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 : 1984-07-01DOI: 10.1179/030634584790419944
J. Nilsson
AbstractThe high temperature, low cycle fatigue behaviour of Alloy 800 has been investigated at 600°C. The results showed that a prior aging treatment of 1000 h in the temperature range 550–600°C improved the fatigue resistance as compared to solution treated material. The strengthening effect was particularly evident in material aged at 550°C. A microstructural investigation revealed that theγ′ precipitate dispersion, which formed intragranularly during aging, interacted very strongly with mobile dislocations. The relatively large γ′ particles formed in material aged at 600°C were bypassed according to the Orowan mechanism, whereas the small γ′ particles in material aged at 550°C were bypassed by particle cutting. Measurements of striation spacings showed that the high fatigue strength of material aged at 550°C was accompanied by a low crack propagation rate. The results can be rationalized in terms of reversibility of plastic flow at the crack tip, which can be expected to be more pronounced when partic...
{"title":"Influence of dislocation–precipitate interaction on low cycle fatigue resistance of Alloy 800 at 600°C","authors":"J. Nilsson","doi":"10.1179/030634584790419944","DOIUrl":"https://doi.org/10.1179/030634584790419944","url":null,"abstract":"AbstractThe high temperature, low cycle fatigue behaviour of Alloy 800 has been investigated at 600°C. The results showed that a prior aging treatment of 1000 h in the temperature range 550–600°C improved the fatigue resistance as compared to solution treated material. The strengthening effect was particularly evident in material aged at 550°C. A microstructural investigation revealed that theγ′ precipitate dispersion, which formed intragranularly during aging, interacted very strongly with mobile dislocations. The relatively large γ′ particles formed in material aged at 600°C were bypassed according to the Orowan mechanism, whereas the small γ′ particles in material aged at 550°C were bypassed by particle cutting. Measurements of striation spacings showed that the high fatigue strength of material aged at 550°C was accompanied by a low crack propagation rate. The results can be rationalized in terms of reversibility of plastic flow at the crack tip, which can be expected to be more pronounced when partic...","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"56 1","pages":"351-356"},"PeriodicalIF":0.0,"publicationDate":"1984-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76180666","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 : 1984-07-01DOI: 10.1179/030634584790419890
J. S. Kallend, Y. Huang
AbstractWhen a metal is deformed cold, a small fraction of the energy expended in its deformation is stored in the crystal lattice associated with crystal defects and their elastic strain fields. There is evidence that grains having different orientations store different amounts of strain energy, although the data available are restricted to just a few grain orientations or are averages over a zone of orientations. A method is described which allows a more complete measurement of the orientation dependence of the stored strain energy of cold work, and is illustrated for the case of 50% cold rolled copper.
{"title":"Orientation dependence of stored energy of cold work in 50% cold rolled copper","authors":"J. S. Kallend, Y. Huang","doi":"10.1179/030634584790419890","DOIUrl":"https://doi.org/10.1179/030634584790419890","url":null,"abstract":"AbstractWhen a metal is deformed cold, a small fraction of the energy expended in its deformation is stored in the crystal lattice associated with crystal defects and their elastic strain fields. There is evidence that grains having different orientations store different amounts of strain energy, although the data available are restricted to just a few grain orientations or are averages over a zone of orientations. A method is described which allows a more complete measurement of the orientation dependence of the stored strain energy of cold work, and is illustrated for the case of 50% cold rolled copper.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"25 1","pages":"381-386"},"PeriodicalIF":0.0,"publicationDate":"1984-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73492642","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 : 1984-07-01DOI: 10.1179/030634584790419917
Yu. I. Ustinovshchikov
Abstract The structure and morphology of Mo2C and VC resulting in secondary hardening of high purity alloys Fe-Mo-C and Fe-V-C during aging at 550°C are studied by electron diffraction, electron and field ion microscopy, X-ray measurements of α Fe matrix unit cell dimensions, and Mossbauer spectroscopy. It is stated that in the early stages of aging, when a sharp decrease in hardness occurs, the process takes place in two directions simultaneously, namely, the formation of cementite particles and the formation of globular clusters of alloying element atoms, the latter being mainly on dislocations and at grain boundaries. During the period of hardness increase, cementite particles are dissolving, and the content, shape, and location of alloying element clusters are changing. The alloying element clusters are mixed zones of M and C atoms, disclike in shape, the discs lying on {100}α planes. Special carbides having the fcc structure are observed at peak hardness in all the alloys investigated. The fcc struct...
摘要:采用电子衍射、电子和场离子显微镜、x射线α Fe基体单位胞尺寸测量和穆斯堡尔光谱等方法研究了高纯合金Fe- mo -C和Fe- v -C在550℃时效过程中引起二次硬化的Mo2C和VC的组织和形貌。结果表明，时效初期硬度急剧下降时，渗碳体颗粒的形成和合金元素原子球状团簇的形成是同时发生的两个方向，后者主要表现为位错和晶界处的位错。在硬度增加的过程中，渗碳体颗粒不断溶解，合金元素团簇的含量、形状和位置都发生了变化。合金元素团簇是M和C原子的混合区，呈圆盘状，圆盘位于{100}α平面上。在所研究的所有合金中均观察到具有fcc结构的特殊碳化物的峰值硬度。fcc的结构…
{"title":"Secondary hardening mechanism of alloy steels","authors":"Yu. I. Ustinovshchikov","doi":"10.1179/030634584790419917","DOIUrl":"https://doi.org/10.1179/030634584790419917","url":null,"abstract":"Abstract The structure and morphology of Mo2C and VC resulting in secondary hardening of high purity alloys Fe-Mo-C and Fe-V-C during aging at 550°C are studied by electron diffraction, electron and field ion microscopy, X-ray measurements of α Fe matrix unit cell dimensions, and Mossbauer spectroscopy. It is stated that in the early stages of aging, when a sharp decrease in hardness occurs, the process takes place in two directions simultaneously, namely, the formation of cementite particles and the formation of globular clusters of alloying element atoms, the latter being mainly on dislocations and at grain boundaries. During the period of hardness increase, cementite particles are dissolving, and the content, shape, and location of alloying element clusters are changing. The alloying element clusters are mixed zones of M and C atoms, disclike in shape, the discs lying on {100}α planes. Special carbides having the fcc structure are observed at peak hardness in all the alloys investigated. The fcc struct...","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"1 1","pages":"337-344"},"PeriodicalIF":0.0,"publicationDate":"1984-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78575905","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 : 1984-07-01DOI: 10.1179/030634584790419935
F. Yılmaz, R. Elliott
AbstractObservations made defining the conditions under which Al halo formation occurs on primary Si and angular Si in pure Al-Si and Sr modified Al-Si alloys during directional solidification with a temperature gradient of 125K cm−1 in the liquid are described. Halo formation is explained in terms of the competitive growth of eutectic Si and primary Al phase.
{"title":"Halo formation in Al-Si alloys","authors":"F. Yılmaz, R. Elliott","doi":"10.1179/030634584790419935","DOIUrl":"https://doi.org/10.1179/030634584790419935","url":null,"abstract":"AbstractObservations made defining the conditions under which Al halo formation occurs on primary Si and angular Si in pure Al-Si and Sr modified Al-Si alloys during directional solidification with a temperature gradient of 125K cm−1 in the liquid are described. Halo formation is explained in terms of the competitive growth of eutectic Si and primary Al phase.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"53 1","pages":"362-366"},"PeriodicalIF":0.0,"publicationDate":"1984-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73055477","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 : 1984-07-01DOI: 10.1179/030634584790419953
Xi He, N. Terao, A. Berghezan
The influence of martensite morphology and its geometrical distribution in ferrite matrix on the mechanical properties and fracture mechanisms of Fe-Mn-C dual phase steels has been studied experimentally. Special attention has been paid to the determination of the fracture mechanisms. Examination of the repolished longitudinal sections of fractured specimens by scanning electron microscopy has revealed that, according to their different morphologies and dispersions, the main mechanism of void formation in these dual phase steels can change from martensite cracking to decohesion at the ferrite/martensite interface. These two features, in turn, can determine the failure mechanisms of the specimen: cleavage or ductile `cup and cone' fracture. In addition, the observed mechanical properties have been related to these modes of fracture.
{"title":"Influence of martensite morphology and its dispersion on mechanical properties and fracture mechanisms of Fe-Mn-C dual phase steels","authors":"Xi He, N. Terao, A. Berghezan","doi":"10.1179/030634584790419953","DOIUrl":"https://doi.org/10.1179/030634584790419953","url":null,"abstract":"The influence of martensite morphology and its geometrical distribution in ferrite matrix on the mechanical properties and fracture mechanisms of Fe-Mn-C dual phase steels has been studied experimentally. Special attention has been paid to the determination of the fracture mechanisms. Examination of the repolished longitudinal sections of fractured specimens by scanning electron microscopy has revealed that, according to their different morphologies and dispersions, the main mechanism of void formation in these dual phase steels can change from martensite cracking to decohesion at the ferrite/martensite interface. These two features, in turn, can determine the failure mechanisms of the specimen: cleavage or ductile `cup and cone' fracture. In addition, the observed mechanical properties have been related to these modes of fracture.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"13 1","pages":"367-373"},"PeriodicalIF":0.0,"publicationDate":"1984-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84226275","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 : 1984-07-01DOI: 10.1179/030634584790419926
B. Garbarz, T. Bold
AbstractExperiments were made to determine the influence of the substructure of hot deformed low alloy steel austenite on the structure and mechanical properties of shear type γ → α transformation products. Four steels having 0.16–0.20%C and additions of Mo, V, and B were used. Immediately before γ → α transformation, austenite was deformed by rolling according to a programme simulating the reduction schedule in industrial plate mills. It was found that the increase in strength owing to the effect of austenite substructure on the structure of shear type γ → α transformation products was small and did not exceed 10%.
{"title":"Influence of austenite substructure on structure and properties of low alloy steels quenched directly from hot deformation temperature","authors":"B. Garbarz, T. Bold","doi":"10.1179/030634584790419926","DOIUrl":"https://doi.org/10.1179/030634584790419926","url":null,"abstract":"AbstractExperiments were made to determine the influence of the substructure of hot deformed low alloy steel austenite on the structure and mechanical properties of shear type γ → α transformation products. Four steels having 0.16–0.20%C and additions of Mo, V, and B were used. Immediately before γ → α transformation, austenite was deformed by rolling according to a programme simulating the reduction schedule in industrial plate mills. It was found that the increase in strength owing to the effect of austenite substructure on the structure of shear type γ → α transformation products was small and did not exceed 10%.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"2673 1","pages":"357-361"},"PeriodicalIF":0.0,"publicationDate":"1984-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81751144","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 : 1984-07-01DOI: 10.1179/030634584790419908
A. Tavassoli, A. Bisson, P. Soulat
AbstractResidual ferrite decomposition in several common austenitic stainless steel weld metals, with or without molybdenum additions, has been investigated. It is shown that ferrite decomposes in α and chromium rich α′ phase at temperatures below about 490°C, whereas it transforms to σ at temperatures above 540°C. At temperatures between 490 and 540°C, α + α′ and α + σ transformations occur simultaneously. These transformations are accompanied by precipitation of carbides and in molybdenum bearing alloys by Mo containing phases such as R. Using the LSW (Lifshitz, Slyozov, Wagner) theory of diffusion controlled coarsening, the apparent activation energy for α → α + α′ decomposition is estimated (Q = 67 kJ mol−1) and a general equation giving the particle size of α′ as a function of aging time and temperature is derived. This equation is used to predict the kinetics of embrittlement owing to α + α′ decomposition at low temperatures.
{"title":"Ferrite decomposition in austenitic stainless steel weld metals","authors":"A. Tavassoli, A. Bisson, P. Soulat","doi":"10.1179/030634584790419908","DOIUrl":"https://doi.org/10.1179/030634584790419908","url":null,"abstract":"AbstractResidual ferrite decomposition in several common austenitic stainless steel weld metals, with or without molybdenum additions, has been investigated. It is shown that ferrite decomposes in α and chromium rich α′ phase at temperatures below about 490°C, whereas it transforms to σ at temperatures above 540°C. At temperatures between 490 and 540°C, α + α′ and α + σ transformations occur simultaneously. These transformations are accompanied by precipitation of carbides and in molybdenum bearing alloys by Mo containing phases such as R. Using the LSW (Lifshitz, Slyozov, Wagner) theory of diffusion controlled coarsening, the apparent activation energy for α → α + α′ decomposition is estimated (Q = 67 kJ mol−1) and a general equation giving the particle size of α′ as a function of aging time and temperature is derived. This equation is used to predict the kinetics of embrittlement owing to α + α′ decomposition at low temperatures.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"68 1","pages":"345-350"},"PeriodicalIF":0.0,"publicationDate":"1984-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78316579","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 : 1984-06-01DOI: 10.1179/030634584790420041
B. Ozturk, E. T. Turkdogan
AbstractResults are given of the equilibrium measurements between liquid Fe containing Si and Al and calcium aluminosilicate melts (with 5%Si02) saturated with CaO at 1600°C and with CaAl4O7 at 1650°C. By incorporating the experimental results of this work with the available data on oxide activities and other slag-metal reactions, the equilibrium relations are derived for Si-Al redox slag-metal reaction. Comments are made on the ladle desulphurization of liquid steel by treatment with lime saturated aluminate slags.
{"title":"Equilibrium S distribution between molten calcium aluminate and steel","authors":"B. Ozturk, E. T. Turkdogan","doi":"10.1179/030634584790420041","DOIUrl":"https://doi.org/10.1179/030634584790420041","url":null,"abstract":"AbstractResults are given of the equilibrium measurements between liquid Fe containing Si and Al and calcium aluminosilicate melts (with 5%Si02) saturated with CaO at 1600°C and with CaAl4O7 at 1650°C. By incorporating the experimental results of this work with the available data on oxide activities and other slag-metal reactions, the equilibrium relations are derived for Si-Al redox slag-metal reaction. Comments are made on the ladle desulphurization of liquid steel by treatment with lime saturated aluminate slags.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"11 1","pages":"299-305"},"PeriodicalIF":0.0,"publicationDate":"1984-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87267961","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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