Pub Date : 1984-01-01DOI: 10.1179/030634584790420302
Y. Ohmori, T. Kunitake
AbstractThe effects of the addition of rare earth metal (REM) on the stress relief cracking susceptibility of low alloy martensite have been examined by slow strain rate tensile tests. The partial dissolution of MnS by austenitization before quenching at temperatures as high as 1573 K promoted the intergranular decohesive mode of fracture in hot tensile tests, and the stabilization of free S atoms by the addition of REM increases ductility at temperatures between 823 and 890 K and the fracture morphology changes to that of intergranular microvoid coalescence. However, in higher temperature deformation in the range from 890 to 973 K, the addition of REM reduces ductility and increases the fraction of intergranular microvoid coalescence at the expense of the transgranular ductile fracture mode. This can be explained in terms of AlN precipitation in relation to the dispersion of fine MnS particles.
{"title":"Effect of addition of rare earth metal on hot tensile properties of low carbon, low alloy martensite","authors":"Y. Ohmori, T. Kunitake","doi":"10.1179/030634584790420302","DOIUrl":"https://doi.org/10.1179/030634584790420302","url":null,"abstract":"AbstractThe effects of the addition of rare earth metal (REM) on the stress relief cracking susceptibility of low alloy martensite have been examined by slow strain rate tensile tests. The partial dissolution of MnS by austenitization before quenching at temperatures as high as 1573 K promoted the intergranular decohesive mode of fracture in hot tensile tests, and the stabilization of free S atoms by the addition of REM increases ductility at temperatures between 823 and 890 K and the fracture morphology changes to that of intergranular microvoid coalescence. However, in higher temperature deformation in the range from 890 to 973 K, the addition of REM reduces ductility and increases the fraction of intergranular microvoid coalescence at the expense of the transgranular ductile fracture mode. This can be explained in terms of AlN precipitation in relation to the dispersion of fine MnS particles.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"68 1","pages":"31-36"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76986449","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 : 1984-01-01DOI: 10.1179/030634584790420357
D. A. Bennett, D. Kirkwood
AbstractTie lines and equilibrium partition coefficients have been measured between liquid and solid in Al rich Al-Cu-Fe alloys by probe microanalysis. Specimens were prepared by equilibration in two and three phase regions, followed by rapid ‘anvil’ quenching. The solidus of the binary Al-Cu system is found to be 50% higher than previously reported leading to a higher value of partition coefficient for copper k 0cu, and this is unaffected by the presence of Fe. The solid solubility of Fe in fcc Al, and the partition coefficient k 0Fe in Al-Cu-Fe, are both higher than previously suspected.
摘要用探针显微分析方法测定了富Al Al- cu - fe合金液固两相之间的铁谱线和平衡分配系数。通过在两相和三相区域进行平衡，然后快速“砧”淬火来制备样品。发现二元Al-Cu体系的固相比先前报道的高50%，导致铜的分配系数更高，而这不受铁的存在的影响。Fe在fcc Al中的固体溶解度和Al- cu -Fe中的分配系数k0fe均高于先前的推测。
{"title":"Phase equilibria between solid aluminium and liquid in Al-Cu and Al-Cu-Fe systems","authors":"D. A. Bennett, D. Kirkwood","doi":"10.1179/030634584790420357","DOIUrl":"https://doi.org/10.1179/030634584790420357","url":null,"abstract":"AbstractTie lines and equilibrium partition coefficients have been measured between liquid and solid in Al rich Al-Cu-Fe alloys by probe microanalysis. Specimens were prepared by equilibration in two and three phase regions, followed by rapid ‘anvil’ quenching. The solidus of the binary Al-Cu system is found to be 50% higher than previously reported leading to a higher value of partition coefficient for copper k 0cu, and this is unaffected by the presence of Fe. The solid solubility of Fe in fcc Al, and the partition coefficient k 0Fe in Al-Cu-Fe, are both higher than previously suspected.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"35 1","pages":"17-21"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76361050","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 : 1984-01-01DOI: 10.1179/030634584790420339
M. R. Ghomashchi, C. Sellars
Abstract An optical and electron metallographic study has been carried out on chill and sand cast M2 grade high speed steel in the as-cast condition and after reheating to temperatures typical of those for hot working for times up to 200 h. The as-cast material contains M2C, MC, and M6C particles, but the M2C decomposes rapidly on reheating. M23C6 was not detected after any of the treatments. Coarse carbides are found both at the centres of dendrites and as interdendritic eutectic pools, with small carbides distributed throughout the as-cast material. Long term treatment causes spheroidization of the eutectic carbides and general coarsening, with preferential growth and impingement of carbides situated on original austenite grain boundaries. The majority of small carbides are dissolved but a few grow preferentially. The structure remains heterogeneous even after long treatment times.
{"title":"Microstructural changes in as-cast M2 grade high speed steel during high temperature treatment","authors":"M. R. Ghomashchi, C. Sellars","doi":"10.1179/030634584790420339","DOIUrl":"https://doi.org/10.1179/030634584790420339","url":null,"abstract":"Abstract An optical and electron metallographic study has been carried out on chill and sand cast M2 grade high speed steel in the as-cast condition and after reheating to temperatures typical of those for hot working for times up to 200 h. The as-cast material contains M2C, MC, and M6C particles, but the M2C decomposes rapidly on reheating. M23C6 was not detected after any of the treatments. Coarse carbides are found both at the centres of dendrites and as interdendritic eutectic pools, with small carbides distributed throughout the as-cast material. Long term treatment causes spheroidization of the eutectic carbides and general coarsening, with preferential growth and impingement of carbides situated on original austenite grain boundaries. The majority of small carbides are dissolved but a few grow preferentially. The structure remains heterogeneous even after long treatment times.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"8 1","pages":"44-48"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84099437","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 : 1984-01-01DOI: 10.1179/030634584790420375
C. Chen, F. Ramberg, J. Evensen
Abstract In this investigation attention was focused on the fracture behaviour of some high strength aluminium alloys in the as-cast and heat treated condition. Fracture is initiated in constituent particles located at grain or dendrite boundaries, and propagates in an intergranular manner. Crack initiation occurs independently of temper condition at a critical stress of about 1000 MN m−2. Fracture toughness varies between 17 and 25 MN m−3/2 depending upon aging condition. The measured toughness can be explained in terms of the critical decohesion stress, the yield stress, and the volume (or distance) over which the critical decohesion stress is exceeded.
{"title":"Fracture behaviour of high strength unworked Al alloys","authors":"C. Chen, F. Ramberg, J. Evensen","doi":"10.1179/030634584790420375","DOIUrl":"https://doi.org/10.1179/030634584790420375","url":null,"abstract":"Abstract In this investigation attention was focused on the fracture behaviour of some high strength aluminium alloys in the as-cast and heat treated condition. Fracture is initiated in constituent particles located at grain or dendrite boundaries, and propagates in an intergranular manner. Crack initiation occurs independently of temper condition at a critical stress of about 1000 MN m−2. Fracture toughness varies between 17 and 25 MN m−3/2 depending upon aging condition. The measured toughness can be explained in terms of the critical decohesion stress, the yield stress, and the volume (or distance) over which the critical decohesion stress is exceeded.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"21 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73360123","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 : 1984-01-01DOI: 10.1179/030634584790419962
B. Ozturk, E. T. Turkdogan
Resultats en relation avec la desulfuration en poche de l'acier avec des laitiers d'aluminate de Ca satures en chaux
与石灰饱和铝酸钙渣在钢包中脱硫有关的结果
{"title":"Equilibrium S distribution between molten calcium aluminate and steel. II: Reaction of Si and Al in steel with calcium aluminate","authors":"B. Ozturk, E. T. Turkdogan","doi":"10.1179/030634584790419962","DOIUrl":"https://doi.org/10.1179/030634584790419962","url":null,"abstract":"Resultats en relation avec la desulfuration en poche de l'acier avec des laitiers d'aluminate de Ca satures en chaux","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"12 1","pages":"306-309"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89440324","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 : 1984-01-01DOI: 10.1179/030634584790420348
T. Ogura, C. Mcmahon
AbstractMeasurements of X-ray line broadening and line shifts were made on intergranular fracture surfaces of a Ni-Cr steel doped with phosphorus. Excess line broadening and line shifts were found to be associated with a layer 1–2 μm thick along the fracture surfaces, and the amounts decreased as the intergranular phosphorus concentration increased. These phenomena are interpreted as being the result of local plastic deformation during brittle crack propagation. The fact that the phenomena decrease with increasing embrittlement is consistent with recent ideas on the relation between the plastic work of fracture and the intergranular cohesive strength, particularly as it is affected by impurity segregation.
{"title":"X-ray study of relation between impurity induced embrittlement and residual strains in intergranular fracture surfaces","authors":"T. Ogura, C. Mcmahon","doi":"10.1179/030634584790420348","DOIUrl":"https://doi.org/10.1179/030634584790420348","url":null,"abstract":"AbstractMeasurements of X-ray line broadening and line shifts were made on intergranular fracture surfaces of a Ni-Cr steel doped with phosphorus. Excess line broadening and line shifts were found to be associated with a layer 1–2 μm thick along the fracture surfaces, and the amounts decreased as the intergranular phosphorus concentration increased. These phenomena are interpreted as being the result of local plastic deformation during brittle crack propagation. The fact that the phenomena decrease with increasing embrittlement is consistent with recent ideas on the relation between the plastic work of fracture and the intergranular cohesive strength, particularly as it is affected by impurity segregation.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"36 1","pages":"37-43"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89577569","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 : 1984-01-01DOI: 10.1179/030634584790420366
H. Wriedt, E. T. Turkdogan
AbstractFor iron alloys containing 1.4–2.9%Si and various Mn and Al contents, the activity of carbon was determined at the ferrite/(ferrite + austenite) phase boundaries by equilibrating the alloys with known mIxtures of hydrogen and methane at atmospheric pressure and temperatures of 940–1080°C. With the aid of available thermodynamic data the measured carbon activities were converted to the corresponding carbon concentrations in order to evaluate the effect of carbon in solution on the position of the γ loop in the temperature–composition phase equilibrium diagram for the iron–silicon alloys.
{"title":"Composition limits of ferritic solid solutions in silicon steels at 950–1100°C","authors":"H. Wriedt, E. T. Turkdogan","doi":"10.1179/030634584790420366","DOIUrl":"https://doi.org/10.1179/030634584790420366","url":null,"abstract":"AbstractFor iron alloys containing 1.4–2.9%Si and various Mn and Al contents, the activity of carbon was determined at the ferrite/(ferrite + austenite) phase boundaries by equilibrating the alloys with known mIxtures of hydrogen and methane at atmospheric pressure and temperatures of 940–1080°C. With the aid of available thermodynamic data the measured carbon activities were converted to the corresponding carbon concentrations in order to evaluate the effect of carbon in solution on the position of the γ loop in the temperature–composition phase equilibrium diagram for the iron–silicon alloys.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"11 1","pages":"27-30"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75602147","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 : 1984-01-01DOI: 10.1179/030634584790420384
K. Wallin, T. Saario, K. Törrönen
AbstractFactors affecting the cleavage fracture stress and the fracture toughness K 1C in steel have been examined. A statistical method based on carbide induced cleavage fracture is proposed, by which it is possible to estimate the fracture toughness and study the effect of different variables. The predictions made are in excellent agreement with experimental results for a variety of microstructures.
{"title":"Statistical model for carbide induced brittle fracture in steel","authors":"K. Wallin, T. Saario, K. Törrönen","doi":"10.1179/030634584790420384","DOIUrl":"https://doi.org/10.1179/030634584790420384","url":null,"abstract":"AbstractFactors affecting the cleavage fracture stress and the fracture toughness K 1C in steel have been examined. A statistical method based on carbide induced cleavage fracture is proposed, by which it is possible to estimate the fracture toughness and study the effect of different variables. The predictions made are in excellent agreement with experimental results for a variety of microstructures.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"10 37 1","pages":"13-16"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79307127","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 : 1984-01-01DOI: 10.1179/030634584790419809
B. Derby, E. Wallach
AbstractIn previous work, a theoretical model for solid state diffusion bonding was described. Possible diffusion bonding mechanisms were identified and mass transport rate equations for each proposed in terms of both process variables (time, temperature, pressure) and material properties. However, the mechanism of mass transfer in the vapour phase was not described since, for many diffusion bonding applications, the contribution from this mechanism will not be significant. For completeness, the vapour phase mass transport rate equations now are derived. In addition, a revised model is presented for the power law creep mechanism, based on considerations of the elastic and plastic deformation of a long triangular ridge. This new approach eliminates the assumptions, implicit in the earlier work, which break down in the later stages of diffusion bonding when the interface is substantially bonded; better agreement with experimental data also is obtained.
{"title":"Diffusion bonding: development of theoretical model","authors":"B. Derby, E. Wallach","doi":"10.1179/030634584790419809","DOIUrl":"https://doi.org/10.1179/030634584790419809","url":null,"abstract":"AbstractIn previous work, a theoretical model for solid state diffusion bonding was described. Possible diffusion bonding mechanisms were identified and mass transport rate equations for each proposed in terms of both process variables (time, temperature, pressure) and material properties. However, the mechanism of mass transfer in the vapour phase was not described since, for many diffusion bonding applications, the contribution from this mechanism will not be significant. For completeness, the vapour phase mass transport rate equations now are derived. In addition, a revised model is presented for the power law creep mechanism, based on considerations of the elastic and plastic deformation of a long triangular ridge. This new approach eliminates the assumptions, implicit in the earlier work, which break down in the later stages of diffusion bonding when the interface is substantially bonded; better agreement with experimental data also is obtained.","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"20 1","pages":"427-431"},"PeriodicalIF":0.0,"publicationDate":"1984-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81944316","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 : 1983-12-01DOI: 10.1179/030634583790420402
R. Ghosh, S. K. Mitra
AbstractA computer program has been developed to simulate the high temperature creep recovery–work hardening rate measurement techniques. The algorithm of the procedure is based on the commonly used mathematical relations between internal stress σi, creep rate ɛ ˙ , applied stress σ, and recovery–work hardening behaviour of metals. The program has subsequently been used to simulate such experiments on a hypothetical model material with known recovery–work hardening behaviour. The analysis of the results reveals significant discrepancies between the measured and the actual recovery as well as work hardening rates particularly when the steady state internal stress/applied stress ratio is low. This has been attributed partly to the use of applied stress in the expressions for the measured recovery r′–work hardening h′ rates and partly to the fact that the measured recovery time ∆t m and the measured instantaneous...
{"title":"Computer simulation of high temperature creep recovery and work hardening rate measurement techniques","authors":"R. Ghosh, S. K. Mitra","doi":"10.1179/030634583790420402","DOIUrl":"https://doi.org/10.1179/030634583790420402","url":null,"abstract":"AbstractA computer program has been developed to simulate the high temperature creep recovery–work hardening rate measurement techniques. The algorithm of the procedure is based on the commonly used mathematical relations between internal stress σi, creep rate ɛ ˙ , applied stress σ, and recovery–work hardening behaviour of metals. The program has subsequently been used to simulate such experiments on a hypothetical model material with known recovery–work hardening behaviour. The analysis of the results reveals significant discrepancies between the measured and the actual recovery as well as work hardening rates particularly when the steady state internal stress/applied stress ratio is low. This has been attributed partly to the use of applied stress in the expressions for the measured recovery r′–work hardening h′ rates and partly to the fact that the measured recovery time ∆t m and the measured instantaneous...","PeriodicalId":18750,"journal":{"name":"Metal science","volume":"48 1","pages":"590-600"},"PeriodicalIF":0.0,"publicationDate":"1983-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90787120","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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