MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90019-0
L.-T. Shiang, C.M. Wayman
{"title":"Maragin behavior of an Fe-19.5Ni-5Mn alloy. III: Mechanical properties","authors":"L.-T. Shiang, C.M. Wayman","doi":"10.1016/0026-0800(89)90019-0","DOIUrl":"10.1016/0026-0800(89)90019-0","url":null,"abstract":"<div><p>A high maraging strength in Fe-Ni-Mn alloys can be achieved at the expense of a marked loss in ductility. Very fine precipitates are observed when peak strength is reached. At peak strength, the Fe-Ni-Mn alloys exhibit brittle failure, mainly along prior austenite grain boundaries, irrespective of the nickel content. The presence of a small amount of retained austenite prior to aging does not improve the ductility. Previous explanation of the embrittlement in Fe-Ni-Mn alloys was attributed to the segregation of Mn to prior austenite grain boundaries. However, this is not fully supported by the present studies. Auger electron spectroscopy reveals no decisive evidence of manganese segregation. Some degree of ductility in the aged martensite may be required in order to prevent brittle fracture. Dual aging recovers part of the ductility and improves the strength slightly. The effect of reversed austenite on ductility may vary, depending on its morphology. Matrix and recrystallized austenite are beneficial to both elongation and reduction of area, but lathlike austenite lowers the elongation, probably because of its lamellar morphology. The lamellar structure of the lath martensite is also detrimental to elongation.</p></div>","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Pages 15-36"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90019-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91208276","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}
MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90021-9
Rong Yong-Hua, Guo Yong-Xiang, Hu Geng Xiang
{"title":"Characterization of M23C6 carbide precipitated at grain boundaries in a superalloy","authors":"Rong Yong-Hua, Guo Yong-Xiang, Hu Geng Xiang","doi":"10.1016/0026-0800(89)90021-9","DOIUrl":"10.1016/0026-0800(89)90021-9","url":null,"abstract":"<div><p>Transmission electron microscopy studies were undertaken to characterize the formation, the imperfection, and the interfacial structure of grain boundary M<sub>23</sub>C<sub>6</sub> carbide in a Ni-base superalloy. The carbides are nucleated separately on both sides of the grain boundary. Each carbide particle possesses a coherent boundary on its matrix side and a high-angle boundary on the other side. The particle is composed of several subgrains, and antiphase boundaries are observed between the subgrain. Lattice defects, such as dislocations, stacking faults, and microtwins, are revealed in the M<sub>23</sub>C<sub>6</sub> carbides.</p></div>","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Pages 47-55"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90021-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83388276","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}
MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90024-4
A. Raman, S. Nasrazadani, L. Sharma
{"title":"Morphology of rust phases formed on weathering steels in various laboratory corrosion tests","authors":"A. Raman, S. Nasrazadani, L. Sharma","doi":"10.1016/0026-0800(89)90024-4","DOIUrl":"10.1016/0026-0800(89)90024-4","url":null,"abstract":"<div><p>The morphology and growth characteristics of rust phases formed on ASTM A-588 weathering steel in three different types of laboratory tests—accelerated atmospheric exposure simulation tests (AAEST), salt fog test, and continuous immersion test in plain as well as salt water—are analyzed using microstructural information obtained from representative exposed specimens studied in a scanning electron microscope (SEM). The ultimate and most dominant phase in the AAEST was α-FeOOH whereas an amorphous phase designated as amorphous bulk (AB) appeared as “cotton bolls” in the adherent, sedimentary layer formed on the steel surface during continuous immersion. Crystalline phases α-, δ-, and γ-FeOOH as well as γ-Fe<sub>2</sub>O<sub>3</sub>.H<sub>2</sub>O were found developed on top of the first-formed sedimentary amorphous layer, containing another amorphous phase designated as amorphous mix (AM). Magnetite was the dominant phase obtained in the salt fog test. It forms in layers and seems to transform to α-FeOOH through formation of whiskers and rods on its surface. Sandy grains of γ-Fe<sub>2</sub>O<sub>3</sub>.H<sub>2</sub>O were also seen in the rusts obtained in this test.</p></div>","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Pages 79-96"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90024-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87547381","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}
MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90026-8
D.L. Davidson, J.B. Campbell
{"title":"Metallography of fatigue crack initiation in coarse-grained Astroloy at 20°C","authors":"D.L. Davidson, J.B. Campbell","doi":"10.1016/0026-0800(89)90026-8","DOIUrl":"10.1016/0026-0800(89)90026-8","url":null,"abstract":"<div><p>Fatigue crack initiation in coarse-grained Astroloy was studied by initiating cracks under bending loads. The specimen was not replicated in order to preserve any debris or extrusions associated with the cracks. Cracks were found to have initiated at pores and along slip lines. Debris and tonguelike extrusions were found coming from some cracks, but not all of them. Illustrations are given of the five different crack extrusion-related phenomena that were observed. It is concluded that the extrusion of material in the form of tonguelike or other debris may accompany the initiation of fatigue cracks, but that it is not a requisite part of the processes causing the crack.</p></div>","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Pages 107-115"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90026-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73064999","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}
MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90027-X
M.J. Witcomb
{"title":"New methods of electro- and jet polishing palladium for transmission electron microscopy","authors":"M.J. Witcomb","doi":"10.1016/0026-0800(89)90027-X","DOIUrl":"10.1016/0026-0800(89)90027-X","url":null,"abstract":"","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Pages 117-120"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90027-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74411014","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}
MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90022-0
S.C. Tjong, G.E. Shih, N.J. Ho
{"title":"Microstructural aspects of low-pressure plasma-sprayed CoNiCrAlY coating on Hastelloy X","authors":"S.C. Tjong, G.E. Shih, N.J. Ho","doi":"10.1016/0026-0800(89)90022-0","DOIUrl":"10.1016/0026-0800(89)90022-0","url":null,"abstract":"<div><p>A Co-32Ni-21Cr-8Al-0.5Y alloy coating was plasma sprayed on Hastelloy X. The microstructure of the coating layer consists of γ phase solid solution, γ′ phase, and Y-rich intermetallic phase. This coating exhibits excellent oxidation and sulfidation resistance after exposure in air and in sodium sulfate at 1,000°C for 60 h, due to the formation of α-Al<sub>2</sub>O<sub>3</sub> oxide scale. However, the presence of chloride in the sodium sulfate leads to rupture of the aluminium oxide scale, and this results in the precipitation of chlorides and sulfides within the coating layer.</p></div>","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Pages 57-67"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90022-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86890306","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}
MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90023-2
A.M. Gokhale
{"title":"Estimation of the average size of plane convex loops in three dimensional microstructure","authors":"A.M. Gokhale","doi":"10.1016/0026-0800(89)90023-2","DOIUrl":"10.1016/0026-0800(89)90023-2","url":null,"abstract":"<div><p>Evolution of microstructures leads to formation of lineal microstructural features, which can be often regarded as plane convex loops. Average loop size is an important stereological parameter for characterization of such features. It is shown that the perimeter averaged caliper diameter <span><math><mtext>D</mtext><msub><mi></mi><mn>p</mn></msub></math></span> is a quantitative descriptor of the average loop size. This parameter is related to the total perimeter of the loops per unit volume, L<sub><em>v</em></sub>, and the total planar area enclosed by the loops per unit volume, A<sub><em>v</em></sub>, as follows: <span><span><span><math><mtext>D</mtext><msub><mi></mi><mn>p</mn></msub><mtext>=</mtext><mtext>4A</mtext><msub><mi></mi><mn>v</mn></msub><mtext>L</mtext><msub><mi></mi><mn>v</mn></msub></math></span></span></span> A practical example involving experimental measurement of <span><math><mtext>D</mtext><msub><mi></mi><mn>p</mn></msub></math></span> is discussed.</p></div>","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Pages 69-77"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90023-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81500949","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}
MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90025-6
F.A. Calvo , M.P. Hierro
{"title":"Metallography of magnesium amalgams with peritectic microstructures","authors":"F.A. Calvo , M.P. Hierro","doi":"10.1016/0026-0800(89)90025-6","DOIUrl":"10.1016/0026-0800(89)90025-6","url":null,"abstract":"<div><p>The microstructures of alloys that show peritectic formation of the compounds Mg<sub>3</sub>Hg and Mg<sub>5</sub>Hg<sub>2</sub> were studied after continuous cooling. Identification of phases present was performed by means of x-ray diffraction, microhardness tests, and differential thermal analysis.</p></div>","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Pages 97-105"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90025-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76717921","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}
MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90018-9
A. Tekin, J.W. Martin
{"title":"High-resolution measurement of crack-tip plastic zone sizes by selected area channelling patterns","authors":"A. Tekin, J.W. Martin","doi":"10.1016/0026-0800(89)90018-9","DOIUrl":"10.1016/0026-0800(89)90018-9","url":null,"abstract":"<div><p>Selected area channelling patterns (SACPs) have been used to measure plastic zones (PZ) associated with fatigue cracks in a nickel-based superalloy MA6000. Refinement of the technique has enabled the PZ dimension to be measured to within ±0.5 μm, which represents an order of magnitude improvement on previously reported work.</p><p>It has been shown, in a series of fatigue tests at various frequencies and temperatures, that the size of the plastic zone at a given value of ΔK varies with the square root of the crack propagation rate.</p></div>","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Pages 1-14"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90018-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76038572","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}
MetallographyPub Date : 1989-01-01DOI: 10.1016/0026-0800(89)90028-1
{"title":"Table of contents for Praktische Metallographie, 10/1988","authors":"","doi":"10.1016/0026-0800(89)90028-1","DOIUrl":"https://doi.org/10.1016/0026-0800(89)90028-1","url":null,"abstract":"","PeriodicalId":100918,"journal":{"name":"Metallography","volume":"22 1","pages":"Page 121"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0026-0800(89)90028-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137289609","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}