{"title":"Strengths and Microstructure of SUS316L Fabricated by Selective Laser Melting","authors":"Kazuki Akino, K. Kakehi","doi":"10.2320/JINSTMET.JAW201610","DOIUrl":"https://doi.org/10.2320/JINSTMET.JAW201610","url":null,"abstract":"The additive manufacturing (AM) process, which can produce highly complex components, has been getting signi cant attention in both industry and academic research. Ti-based alloys, Ni-based superalloys, and Co-Cr-based alloys have been widely investigated. However, as Ni-based superalloys have precipitated phases such as the γ′ and γ′′ phases, and Ti-based alloys and Co-Cr-based alloys are multiphase alloys which have phase transformation, it is dif cult to clarify the factors in the AM process that in uence the strength of these alloys. In this study, SUS316L stainless steel, which is a single-phase solid-solution alloy and does not have precipitated phases, was used to investigate the effect of speci c factors in the AM process on anisotropy or mechanical properties, and the strengthening mechanism in the AM process in comparison with SUS316L plastic-forming (PF) material. The AM SUS316L was fabricated by selective laser melting using an ytterbium ber laser from ne metallic powder. We found that the coarse columnar grains grew up along the built direction and the dislocation cell structures which were induced during the AM process into the AM material. During the solution heat treatment, dislocation recovery was observed. The AM specimens showed higher tensile and creep strength compared with the conventional material (the PF material) because of the high dislocation density. The ductility of the AM specimens was lower than that of the conventional material because of defects caused by a lack of fusion at the molten pool boundaries. Furthermore, the specimens whose loading direction corresponds to the built direction showed lower strength and elongation than the specimens whose loading direction was perpendicular to the built direction due to the oriented defects. [doi:10.2320/matertrans.M2017163]","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90346098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Formation Mechanism of Lath Martensite in Steels","authors":"Y. Murata","doi":"10.2320/JINSTMET.J2016033","DOIUrl":"https://doi.org/10.2320/JINSTMET.J2016033","url":null,"abstract":"Lath martensite formed in low carbon steels plays a crucial role in the mechanical properties of heat-resistant steels containing approximately 0.1 mass%C. Lath martensite exhibits a hierarchical microstructure comprising packets, blocks and laths. Martensitic transformation is the phase transformation accompanying ordered shear deformation without atom diffusion. The hierarchical microstructure is formed as a result of the relaxation of the strain energy caused by the deformation; however, to the best of our knowledge, the formation mechanism of this microstructure has not been understood thus far. In this paper, the experimental results and phenomenological formation mechanism reported thus far are reviewed, and a new mechanism (including two types of slip deformation (TTSD) model) is introduced, which is constructed by independently considering two kinds of slip deformations using the slip deformation model proposed by Khachaturyan. In addition, the TTSD model allows for the simulation of the martensite phase formation by the phaseeld method. Furthermore, the TTSD model permits the prediction of lath martensite features including the existence of sub-blocks and high density of dislocations in lath. In particular, the presence of laths in a block structure is clearly explained by the TTSD model for the rst time. [doi:10.2320/matertrans.M2016430]","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76018230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Indentation Orientation on the Onset of Plastic Deformation for a MAX Phase Ti 2 AlC","authors":"Wada Yusuke, Sekido Nobuaki, Ohmura Takahito, Yoshimi Kyosuke","doi":"10.2320/JINSTMET.J2017042","DOIUrl":"https://doi.org/10.2320/JINSTMET.J2017042","url":null,"abstract":"Polycrystalline Ti2AlC alloys were prepared by spark plasma sintering of high purity elemental materials, and subsequently annealed at 1500°C for 24 h. Nanoindentation behavior was studied on the grains with their surface normal directions parallel to 〈3362〉, 〈4481〉, 〈0001〉 and 〈1120〉. During loading of nanoindentation, pop–in events were found to occur for all the indentation directions. The critical loads of the first pop–in observed for the indentation directions parallel to 〈1120〉 and 〈0001〉 were higher than those for 〈3362〉 and 〈4481〉. Surface topography around the residual indents suggests that the basal slip dominates the plastic deformation upon indentation. These results suggest that the nucleation of the basal dislocation is a major barrier for the onset of plastic deformation underneath the indenter. [doi:10.2320/jinstmet.J2017042]","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80840133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hyperbaric-Oxygen Accelerated Corrosion Test of Iron in Cement Paste and Mortar","authors":"K. Doi, S. Hiromoto, E. Akiyama","doi":"10.2320/JINSTMET.J2017030","DOIUrl":"https://doi.org/10.2320/JINSTMET.J2017030","url":null,"abstract":"","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81012550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hydroxyapatite Dispersed Magnesium-Based Composite Produced from Pulverized Magnesium Alloy Powder and Its Mechanical Properties","authors":"H. Watanabe, Takane Motoyama, N. Ikeo, T. Mukai","doi":"10.2320/JINSTMET.J2017036","DOIUrl":"https://doi.org/10.2320/JINSTMET.J2017036","url":null,"abstract":"A magnesium matrix composite made of Mg–1mass%Ca and 10 vol% hydroxyapatite (HAp) particles was synthesized. The alloy powder was processed by pulverization of the small blocks of the alloy ingot using a high–speed blade grinder. Unreacted composite was successfully produced by extruding the two component powders at a temperature of 538 K. In the extruded composites, the grains of the magnesium matrix were equiaxed and the matrix grain size was 3.9 μm. As for the HAp particles, both thin clustering and severe agglomeration with the size of ~30 μm were observed. The Young's modulus, tensile yield strength and tensile strength of the extruded composite were 39 GPa, 101 MPa and 153 MPa, respectively. The damping capacity of the composite was higher than that of extruded magnesium. The composite also showed good forgeability at a temperature of 523 K. However, quite high impurity contents of Fe (0.130 mass%) and Ni (0.010 mass%) were introduced in the magnesium matrix of the composite, probably as a result of contamination that accumulates during the processing (pulverization) of the alloy powder. [doi:10.2320/jinstmet.J2017036]","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82616695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dynamic Material Flow Analysis of Copper and Copper Alloy in Global Scale —Forecast of In-Use Stock and Inputs and the Estimation of Scrap Recovery Potential—","authors":"Akihiro Yoshimura, Yasunari Matsuno","doi":"10.2320/JINSTMET.J2017034","DOIUrl":"https://doi.org/10.2320/JINSTMET.J2017034","url":null,"abstract":"The recovery of copper ( Cu ) from secondary sources has received much attention because of its scarcity of natural resources. In this work, we estimated the input, in - use stock and discard of copper and copper alloy during 1950 - 2015 in global scale, and forecast them until 2050. In addition, we estimated the potential of scrap recovery for copper / copper alloys. It was estimated that the total amount of in - use stock of copper and copper alloy were 177 , 000 kt and 44 , 200 kt in 2015, respectively. The in - use stock, discard and input of copper in 2050 will reach 381 , 000 - 588 , 000 kt, 15 , 400 - 22 , 200 kt and 18 , 990 - 33 , 000 kt, respectively, whereas those for copper alloy will reach 77, 500 - 134 , 000 kt, 3 , 020 - 4 , 680 kt and 3 , 760 - 7 , 200 kt, respectively. The copper content in recov - erable scraps of copper and copper alloy will reach 15 , 100 - 27 , 300 kt, and this accounts for 55 . 1 - 79 . 0 % of copper content in annual input of copper and copper alloy in 2050. The range in forecast was caused by the difference in the saturation amount","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79857065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dependence of Load Angle on Static Strength of Resistance Spot Welded Lap Joint in Combined Load Test","authors":"T. Akiyama, T. Kitamura, Tetsushi Ono","doi":"10.2320/JINSTMET.J2017040","DOIUrl":"https://doi.org/10.2320/JINSTMET.J2017040","url":null,"abstract":"Strength of resistance spot welded lap joint is a very interesting task. JIS prescribes tensile shear test and cross tension test as a realistic environment in combined load. Then, a lot of strength prediction equations have been proposed. And these features are in the use of a threshold value based on the base material strength as a fracture condition. The relational expression between the cross tension strength and the opening angle deals only with the infl uence of the opening angle on the axial force acting geometrically on the base metal. But it explains the experimental results well. The strength of resistance spot welded lap joint in combined load is known to exhibit dependence of load angle. But it is not clear whether the cause is only the geometric infl uence as shown by the past equations or the fracture mechanism change depend on the load angle. In this study, we examined how much dependence of load angle can be explained by macro geometric factors using a material dynamics model, before studying the micro fracture mechanism depend on the load angle in the vicinity of the crack initiation part of the nugget. As a result, we were able to explain the dependence of load angle with the macro model. [doi:10.2320/jinstmet.J2017040]","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83459538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Takizawa, Kyohei Watanabe, T. Kajita, Kosei Sumikawa, T. Masuda, M. Yumoto, Yoshiharu Otagiri, Z. Horita, Z. Horita
{"title":"Incremental feeding high-pressure sliding for achieving large area of severe plastic deformation","authors":"Y. Takizawa, Kyohei Watanabe, T. Kajita, Kosei Sumikawa, T. Masuda, M. Yumoto, Yoshiharu Otagiri, Z. Horita, Z. Horita","doi":"10.2320/JINSTMET.J2017038","DOIUrl":"https://doi.org/10.2320/JINSTMET.J2017038","url":null,"abstract":"In this study, high - pressure sliding is combined with incremental feeding so that a severely deformed area is enlarged without increasing the machine capacity. With this combined process ( called the incremental feeding high - pressure sliding: IF - HPS ) , a sheet sample is lateraly fed every after sliding under high pressure. The IF - HPS process was applied to a Ni - based superalloy ( Inconel 718 ) and a Ti - 6Al - 7Nb alloy ( F1295 ) for grain refinement. The applicability of the IF - HPS process is examined with the advent of superplasticity through the grain refinement. Vickers microhardness measurement shows that the hardness is higher in the area of the second pass than the first pass for both Inconel 718 and F1295 but the hardness increase is more prominent in the area where the second passes is superimposed on the first passparticularly for the Inconel 718. After tensile testing, superplastic elongation more than 400 % appears in the superimposed areas of both Inconel 718 and F1295. For the F1295 alloy, the area of the second pass also exhibits a suplerplastic elongation of 400 % . Analysis by finte element method ( FEM ) reveals that strain introduced by outwardflow from the severely deformed area is sensitive to friction coefficient between the sample and anvil outside of the flat contact area. The strain due to this outwardflow conributes to the grain refinement in the second pass for the F1295 alloy but insuf ficient for the Inconel 718. [ doi:10 . 2320 / jinstmet.J2017038 ]","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78105570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"最高温度が 1073 KにおけるNb含有フェライト系ステンレス鋼の熱疲労過程の組織変化","authors":"純一 濱田, 尚希 森弘, 治彦 梶村","doi":"10.2320/JINSTMET.JC201701","DOIUrl":"https://doi.org/10.2320/JINSTMET.JC201701","url":null,"abstract":"","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75604219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hiroaki Rikihisa, Takashi Mori, M. Tsushida, H. Kitahara, S. Ando
{"title":"Influence of Yttrium Addition on Plastic Deformation of Magnesium","authors":"Hiroaki Rikihisa, Takashi Mori, M. Tsushida, H. Kitahara, S. Ando","doi":"10.2320/JINSTMET.J2017016","DOIUrl":"https://doi.org/10.2320/JINSTMET.J2017016","url":null,"abstract":"In this study, tensile tests of Mg - Y alloy single crystals and polycrystals were carried out to investigate influence of yttrium on activities of <c + a> slip systems and a relationship between ductility of magnesium and active <c + a> slip systems. Tensile directions of the single crystals and the polycrystals were parallel to ( 0001 ) and its rolling direction, respectively. Both tests were carried out at room temperature. Yield stress and ductility of Mg -( 0 . 6 - 1 . 1 ) at % Y alloy single crystals were higher than that of pure Mg and the crystals were yielded due to first order pyramidal <c + a> slip ( FPCS ) . Mg - 0 . 9 at % Y alloy polycrystals showed higher ductility than pure Mg. The number of grains in which second order pyramidal slip can be activated was larger than that of non - basal slips in pure Mg, while the number for FPCS was increased with increasing strain in Mg - 0 . 9 at % Y alloy. We supposed that high ductil - ity of Mg - 0 . 9 at % Y alloy would be caused activation of FPCS by yttrium addition. [ doi:10 . 2320 / jinstmet.J2017016 ]","PeriodicalId":17337,"journal":{"name":"Journal of The Japan Institute of Metals","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80897182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}