Pub Date : 1984-12-01DOI: 10.1179/030634584790419656
G. Marshall
AbstractThe development of microstructure in a Cu-Ni-Al-Mn alloy has been observed by optical and transmission electron microscopy. Solution treatment followed by water quenching does not produce a completely random solid solution and electron diffraction suggests that there may be short range order. Isothermal aging produces precipitation of θ phase (Ni3Al, L12 structure) homogeneously in the matrix, discontinuously at grain boundaries, and heterogeneously at grain boundaries. The homogeneously nucleated θ phase coarsens from spheres to cubes to plates, because of the necessity to reduce the elastic strain energy associated with the coherent precipitates, which also encourages particle alignment at and below 600°C. A classical discontinuous precipitation reaction is observed at all temperatures studied, but the proportion of affected grain boundaries is reduced as the temperature rises. After termination of the reaction which occurs very rapidly, the θ rods coarsen at two different rates depending on the...
{"title":"Microstructural development in commercial Cu-Ni-Al-Mn alloy","authors":"G. Marshall","doi":"10.1179/030634584790419656","DOIUrl":"https://doi.org/10.1179/030634584790419656","url":null,"abstract":"AbstractThe development of microstructure in a Cu-Ni-Al-Mn alloy has been observed by optical and transmission electron microscopy. Solution treatment followed by water quenching does not produce a completely random solid solution and electron diffraction suggests that there may be short range order. Isothermal aging produces precipitation of θ phase (Ni3Al, L12 structure) homogeneously in the matrix, discontinuously at grain boundaries, and heterogeneously at grain boundaries. The homogeneously nucleated θ phase coarsens from spheres to cubes to plates, because of the necessity to reduce the elastic strain energy associated with the coherent precipitates, which also encourages particle alignment at and below 600°C. A classical discontinuous precipitation reaction is observed at all temperatures studied, but the proportion of affected grain boundaries is reduced as the temperature rises. After termination of the reaction which occurs very rapidly, the θ rods coarsen at two different rates depending on the...","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"5 1","pages":"553-559"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87168591","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 : 1984-12-01DOI: 10.1179/030634584790419629
I. Saunders, J. Nutting
AbstractA combined torsion and compression mode of deformation has been used to deform copper and silver to equivalent tensile true strains of ≃ 8. The microstructures have been determined by transmission electron microscopy. It has been found that at true strains within the range 4–8 there is no change in microstructure or Vickers hardness with strain. The type of microstructure is that of fine grains, similar to those formed by recrystallization. The yield stress of the fine grained structures in .copper corresponds to that predicted from the Hall- Petch relationship.
{"title":"Deformation of metals to high strains using combination of torsion and compression","authors":"I. Saunders, J. Nutting","doi":"10.1179/030634584790419629","DOIUrl":"https://doi.org/10.1179/030634584790419629","url":null,"abstract":"AbstractA combined torsion and compression mode of deformation has been used to deform copper and silver to equivalent tensile true strains of ≃ 8. The microstructures have been determined by transmission electron microscopy. It has been found that at true strains within the range 4–8 there is no change in microstructure or Vickers hardness with strain. The type of microstructure is that of fine grains, similar to those formed by recrystallization. The yield stress of the fine grained structures in .copper corresponds to that predicted from the Hall- Petch relationship.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"40 1","pages":"571-576"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87509009","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 : 1984-12-01DOI: 10.1179/030634584790419647
Tomoshi Takahashi, M. Kato, Y. Minamino, T. Yamane
AbstractThe interdiffusion coefficients in the α fcc phase of Cu-Ni-Zn alloys DZnZnCu, DZnNiCu, DNiNiCu and DNiZiCu at 1133 K have been determined by an extended Boltzmann-Matano method. The major coefficients DZnZnCu and DNiNiCu are positive, and the crosscoefficients DZnNiCuand DNiZnCu are negative. A pronounced concentration dependence of the four interdiffusion coefficients is observed, DZnZnCu being particularly sensitive to composition. From the estimated, values of interaction parameters, it is considered that the interaction energy of the Ni-Zn bond at 1131 K is much larger than the values for the Cu-Zn and Cu-Ni bonds. The tracer diffusion coefficients DZu*, DNi* and DCu* calculated from the equations of Zieboldand Ogilvie are in the order DZu* > DCu* > DNi*. In addition, the calculated intrinsic diffusion coefficients DZnZnCu and DNiNiCu are positive, and the four other coefficients are negative.
{"title":"Ternary diffusion in Cu-Ni-Zn alloys at 1133 K","authors":"Tomoshi Takahashi, M. Kato, Y. Minamino, T. Yamane","doi":"10.1179/030634584790419647","DOIUrl":"https://doi.org/10.1179/030634584790419647","url":null,"abstract":"AbstractThe interdiffusion coefficients in the α fcc phase of Cu-Ni-Zn alloys DZnZnCu, DZnNiCu, DNiNiCu and DNiZiCu at 1133 K have been determined by an extended Boltzmann-Matano method. The major coefficients DZnZnCu and DNiNiCu are positive, and the crosscoefficients DZnNiCuand DNiZnCu are negative. A pronounced concentration dependence of the four interdiffusion coefficients is observed, DZnZnCu being particularly sensitive to composition. From the estimated, values of interaction parameters, it is considered that the interaction energy of the Ni-Zn bond at 1131 K is much larger than the values for the Cu-Zn and Cu-Ni bonds. The tracer diffusion coefficients DZu*, DNi* and DCu* calculated from the equations of Zieboldand Ogilvie are in the order DZu* > DCu* > DNi*. In addition, the calculated intrinsic diffusion coefficients DZnZnCu and DNiNiCu are positive, and the four other coefficients are negative.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"4 1","pages":"580-586"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75880543","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 : 1984-12-01DOI: 10.1179/030634584790419683
Y. Ustinovshikov
AbstractThe use of only the thermodynamic approach in the investigation of the phenomena of temper embrittlement and impurity segregation is insufficient for the complete understanding of such processes. To explain correctly those phenomena, it is suggested that the phase transformation theory and the data from structural studies for different stages of aging be used in conjunction with the thermodynamic method. Such an approach makes it possible to explain the effects of each solute upon the process of impurity segregation.
{"title":"Effects of alloying elements, impurities, and carbon on temper embrittlement of steels","authors":"Y. Ustinovshikov","doi":"10.1179/030634584790419683","DOIUrl":"https://doi.org/10.1179/030634584790419683","url":null,"abstract":"AbstractThe use of only the thermodynamic approach in the investigation of the phenomena of temper embrittlement and impurity segregation is insufficient for the complete understanding of such processes. To explain correctly those phenomena, it is suggested that the phase transformation theory and the data from structural studies for different stages of aging be used in conjunction with the thermodynamic method. Such an approach makes it possible to explain the effects of each solute upon the process of impurity segregation.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"36 1","pages":"545-548"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73789384","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 : 1984-12-01DOI: 10.1179/030634584790419638
K. Mawella
AbstractA theory of three dimensional heat flow, which has been used in metallurgical applications such as welding, is used to predict the heat flow distribution in electron beam rapidly quenched surfaces of metal. The results of the computerized heat flow analysis as applied to ultrahigh strength steel surfaces show that the cooling rates at points nearer to the surface are higher than those at greater depths. It is also shown that when the same traverse speed is used, the melt depth increases with increasing beam power. Theoretical results are compared with experimental results. Since the energy transfer efficiency from electron beams to metal surfaces is high, only low power electron beams are necessary to rapidly quench the metal surfaces. It is found that in the range of low power electron beams used in these experiments, the experimental results are in good agreement with the theoretical results.
{"title":"Heat flow distribution in electron beam rapidly quenched surfaces","authors":"K. Mawella","doi":"10.1179/030634584790419638","DOIUrl":"https://doi.org/10.1179/030634584790419638","url":null,"abstract":"AbstractA theory of three dimensional heat flow, which has been used in metallurgical applications such as welding, is used to predict the heat flow distribution in electron beam rapidly quenched surfaces of metal. The results of the computerized heat flow analysis as applied to ultrahigh strength steel surfaces show that the cooling rates at points nearer to the surface are higher than those at greater depths. It is also shown that when the same traverse speed is used, the melt depth increases with increasing beam power. Theoretical results are compared with experimental results. Since the energy transfer efficiency from electron beams to metal surfaces is high, only low power electron beams are necessary to rapidly quench the metal surfaces. It is found that in the range of low power electron beams used in these experiments, the experimental results are in good agreement with the theoretical results.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"65 1","pages":"549-552"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72818967","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 : 1984-12-01DOI: 10.1179/030634584790419674
C. J. Ball
AbstractThe X-ray powder diffraction pattern of titanium carbosulphide has been calculated from crystal structure data and has been shown to be in good agreement with observations, but to differ significantly from previously published patterns. In a steel in which the concentration of sulphur was more than sufficient to form titanium carbosulphide with all the carbon present, hexagonal TiS was formed and not τ Ti2S. It is argued, on the basis of this and other evidence, that the phase initially identified as τ Ti2S was, in fact, titanium carbosulphide, and that τ Ti2S does not exist.
{"title":"X-ray powder diffraction patterns of titanium carbosulphide and τ titanium sulphide","authors":"C. J. Ball","doi":"10.1179/030634584790419674","DOIUrl":"https://doi.org/10.1179/030634584790419674","url":null,"abstract":"AbstractThe X-ray powder diffraction pattern of titanium carbosulphide has been calculated from crystal structure data and has been shown to be in good agreement with observations, but to differ significantly from previously published patterns. In a steel in which the concentration of sulphur was more than sufficient to form titanium carbosulphide with all the carbon present, hexagonal TiS was formed and not τ Ti2S. It is argued, on the basis of this and other evidence, that the phase initially identified as τ Ti2S was, in fact, titanium carbosulphide, and that τ Ti2S does not exist.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"80 1","pages":"577-579"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91291775","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 : 1984-12-01DOI: 10.1179/030634584790419665
T. Sheppard
AbstractAn aluminium alloy for potential high temperature application containing substantial additions of chromium, iron, and nickel has been examined. Structural changes during consolidation, phase identification, and structural stability of the extrudate have been assessed. The rapidly solidified powders are non-spherical and contain a considerable proportion of particles in the size range 30–60 μm. The microstructure of the powder particles exhibits fine, individual spherulites surrounded by an aluminium matrix containing fine precipitates. X-ray analysis shows that the powder contains α Al, Al13Cr2, and an unknown phase or phases, the spherulites being a mixture of all these phases. The powder is readily cold compacted and a linear relationship between compaction pressure and density is shown. Clearly defined powder particles are retained in the billet section during the extrusion sequence and a break-up of oxide envelopes occurs, but no oxide presence is found in the extrudates. The multiphase spheru...
{"title":"Structural aspects of rapidly solidified Al-Cr-Fe-Ni alloy","authors":"T. Sheppard","doi":"10.1179/030634584790419665","DOIUrl":"https://doi.org/10.1179/030634584790419665","url":null,"abstract":"AbstractAn aluminium alloy for potential high temperature application containing substantial additions of chromium, iron, and nickel has been examined. Structural changes during consolidation, phase identification, and structural stability of the extrudate have been assessed. The rapidly solidified powders are non-spherical and contain a considerable proportion of particles in the size range 30–60 μm. The microstructure of the powder particles exhibits fine, individual spherulites surrounded by an aluminium matrix containing fine precipitates. X-ray analysis shows that the powder contains α Al, Al13Cr2, and an unknown phase or phases, the spherulites being a mixture of all these phases. The powder is readily cold compacted and a linear relationship between compaction pressure and density is shown. Clearly defined powder particles are retained in the billet section during the extrusion sequence and a break-up of oxide envelopes occurs, but no oxide presence is found in the extrudates. The multiphase spheru...","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"23 3 1","pages":"561-570"},"PeriodicalIF":0.0,"publicationDate":"1984-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77510434","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 : 1984-11-01DOI: 10.1179/030634584790419700
H. M. Chan, F. J. Humphreys
Abstract An Al-6 wt-%Ni alloy containing a volume fraction of 0.1 of 1.1 μm dia. particles was deformed 95% by cold rolling and annealed. Recrystallization was nucleated in the vicinity of the particles, and the orientation of the new grains was investigated by X-ray and electron diffraction. The orientation of the recrystallization nuclei was found to be almost random, with the majority of nuclei being misoriented by 15–45° from the adjacent matrix, and this was interpreted in terms of nucleation within the deformation zone at the particles. In the fully recrystallized material, however, the texture was significantly sharper than in the deformed material, and this was ascribed to the more rapid growth of grains of selected orientations.
{"title":"Effect of particle stimulated nucleation on orientation of recrystallized grains","authors":"H. M. Chan, F. J. Humphreys","doi":"10.1179/030634584790419700","DOIUrl":"https://doi.org/10.1179/030634584790419700","url":null,"abstract":"Abstract An Al-6 wt-%Ni alloy containing a volume fraction of 0.1 of 1.1 μm dia. particles was deformed 95% by cold rolling and annealed. Recrystallization was nucleated in the vicinity of the particles, and the orientation of the new grains was investigated by X-ray and electron diffraction. The orientation of the recrystallization nuclei was found to be almost random, with the majority of nuclei being misoriented by 15–45° from the adjacent matrix, and this was interpreted in terms of nucleation within the deformation zone at the particles. In the fully recrystallized material, however, the texture was significantly sharper than in the deformed material, and this was ascribed to the more rapid growth of grains of selected orientations.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"115 1","pages":"527-530"},"PeriodicalIF":0.0,"publicationDate":"1984-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89572384","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 : 1984-11-01DOI: 10.1179/030634584790419728
U. Lenel, R. Honeycombe
AbstractThe formation of austenite during intercritical annealing of ferrite–spheroidized cementite and ferrite–pearlite microstructures in low carbon steels has been investigated. It has been established that austenite which nucleates at a ferrite grain boundary does so with a Kurdjumov–Sachs crystallographic orientation relationship with one or both ferrite grains. It has been shown also that austenite/ferrite interfaces displaying low energy planar facets need not have a rational crystallographic relationship across them. The size and distribution of cementite particles in the parent material, particularly in relation to ferrite grain boundaries, has a marked effect on the distribution and morphology of austenite; the morphologies are similar to those displayed by proeutectoid ferrite. Austenite growth has been shown to be initially associated with carbon diffusion through austenite and subsequently with carbon diffusion through ferrite. Primary and secondary WidmansHitten sideplates occur only when di...
{"title":"Morphology and crystallography of austenite formed during intercritical annealing","authors":"U. Lenel, R. Honeycombe","doi":"10.1179/030634584790419728","DOIUrl":"https://doi.org/10.1179/030634584790419728","url":null,"abstract":"AbstractThe formation of austenite during intercritical annealing of ferrite–spheroidized cementite and ferrite–pearlite microstructures in low carbon steels has been investigated. It has been established that austenite which nucleates at a ferrite grain boundary does so with a Kurdjumov–Sachs crystallographic orientation relationship with one or both ferrite grains. It has been shown also that austenite/ferrite interfaces displaying low energy planar facets need not have a rational crystallographic relationship across them. The size and distribution of cementite particles in the parent material, particularly in relation to ferrite grain boundaries, has a marked effect on the distribution and morphology of austenite; the morphologies are similar to those displayed by proeutectoid ferrite. Austenite growth has been shown to be initially associated with carbon diffusion through austenite and subsequently with carbon diffusion through ferrite. Primary and secondary WidmansHitten sideplates occur only when di...","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"23 1","pages":"503-510"},"PeriodicalIF":0.0,"publicationDate":"1984-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75040625","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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