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Failure Analysis of Austenitic Stainless Steel Implant Screws and Prospection of Chemical Composition Using Artificial Intelligence

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World Journal of Engineering and Technology 2022年第1期10卷 98-118页

作者： Alfonso monzamodeth Román-Sedano Bernardo Campillo Fermín Castillo Osvaldo Flores Facultad de Química Universidad Nacional Autónoma de México Ciudad de México México Instituto de Ciencias Físicas Universidad Nacional Autónoma de México Cuernavaca Morelos México

In this work, austenitic stainless steel screws employed in a locking compression plate for veterinarian use were investigated. These types of implants are widely utilized in bone fractures healing. Two surgical screws were extracted due to the observation of slight superficial red rust colorizing on one of the screw implants, visual evidence of probable screw rusting. From the same implant, another screw was extracted simultaneously without visual evidence of rusting. In order to characterize and analyze the different behavior of both screws, the chemical composition was characterized by atomic absorption and energy dispersive X-ray spectroscopy (EDS) coupled to a scanning electron microscope (SEm). Also, the screws were studied by metallography, optical microscopy (om), Vickers microhardness tests, and SEm analysis. On the other hand, a prospection for alloy chemical composition limits of these types of implants was performed based on the Schaeffler-Delong diagram and the ASTm F-138 standard. To analyze the effect of the chemical composition, heat treatment, microstructure, pitting resistance equivalent number (PRE) and stacking fault energy (SFE), a genetic algorithm (GA) and an artificial neural network (Ann) were used. In accordance with the elemental analysis, the surgical screws do not fulfill the ranges of the chemical composition established by the ASTm F-138 standard. Furthermore, there were found differences between the microstructures of the screws. In regard to the prospection, the results of GA and Ann support the proposed chemical composition region on the Schaeffler-Delong diagram. The corrosion failure was associated with severe plastic deformation and the presence of precipitates. The proposal can minimize the cause of failures in these types of austenitic stainless steel implants.

关键词： Implant Screw Failure Analysis Genetic Algorithm Artificial neural network Austenitic Stainless Steel

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Characterization of the negative carbon isotope shift in segment C2,its global implications as a harbinger of OAEla

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Science China Earth Sciences 2017年第1期60卷 30-43页

作者： Jander SOCORRO Florentin J-m. R. mAURRASSE Yosmel SAnCHEZ-HERnAnDEZ Department Earth and Environment Florida International University 11200 SW 8 Street Miami FL 33199 USA

Lower Cretaceous C-isotope records show intermittent negative/positive spikes, and consistent patterns of coevalchemostratigraphic curves thus document shifts that signal simultaneous responses of temporal changes in the global carbon reservoir. The standard pattern registered by the δ13Corg and δ13Ccarb in Lower Aptian sediments includes distinct isotope segments C1 to C8 （menegatti et al., 1998）. In the E1 Pui section, Organy Basin, Spain, C-isotope segment C2 is the longest interval preceding segments C3-C6 associated with oceanic anoxic event la （OAE la）, and reveals a distinct negative shift of-1.8‰ to -2.23‰ defining the C-isotope pattern within that interval. Total inorganic carbon （TIC）, total organic carbon （TOC）, δ13Corg, microfacies, n-alkanes show no difference before, during, or after the negative inflection. The biomarkers indicate that organic matter （om） mainly originates from algal/microbial sources because short-chain length homologues （〈 nCtg） dominate, nC2o through nC25 indicate some contribution from aquatic vegetation, but little from higher plants （〉nC20, as also suggested by the terrestrial/aquatic ratio ofn-alkanes or （TAR） = [（nf27＋nf29＋nC31）/（nC15＋nCt7＋rlCt9）] （averages 0.085）. We suggest that conjoint pulses of contemporaneous LIPs （Ontong Java） and massive explosive volcanism in northeast Asia, the Songliao Basin （SB-V）, best conform to plausible causes of the negative intra-C2 carbon isotopic excursion （CIE） at that time. Because of its apparent common occurrence the intra-C2 inflection could be a useful marker harbinger to the more pronounced CIE C3, the hallmark of OAE 1 a.

关键词： Oceanic Anoxic Event la (OAEla) Aptian Organy Basin Chemostratigraphy Pyrenees

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Processing,microstructure and mechanical properties of bimodal size SiCp reinforced AZ31B magnesium matrix composites

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Journal of magnesium and Alloys 2015年第2期3卷 162-167页

作者： m.J.Shen m.F.Zhang W.F.Ying College of Engineering Shenyang Agricultural UniversityShenyang 110866PR China Liaoning Provincial Gem Quality Supervision and Inspection Center Shenyang 110000PR China College of Chemical Engineering and materials Science Eastern Liaoning UniversityDandong 118003PR China

The bimodal size SiC particulates(SiCp)reinforced magnesium matrix composites with different ratios of micron SiCp and nano SiCp(m-SiCp:n-SiCp=14.5:0.5,14:1,and 13.5:1.5)were prepared by semisolid stirring assisted ultrasonic vibration *** AZ31B alloy and all as-cast SiCp/AZ31B composites were extruded at 350℃ with the ratio of 12:*** characterization of the extruded m14+n1(m-SiCp:n-SiCp=14:1)composite revealed the uniform distribution of bimodal size SiCp and significant grain *** microscopy(om)observation showed that,compared with the m14.5+n0.5(m-SiCp:n-SiCp=14.5:0.5)composite,there are more recrystallized grains in m14+n1(m-SiCp:n-SiCp=14:1)and m13.5+n1.5(m-SiCp:n-SiCp=13.5:1.5)composites,but in comparison to the m13.5+n1.5 composite,the average grain size of the m14+n1 composite is slightly *** evaluation of mechanical properties indicated that the yield strength and ultimate tensile strength of the m14+n1 composite were obviously increased compared with other composites.

关键词： magnesium matrix composite microstructure mechanical properties

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microstructure,mechanical and wear properties of aluminum borate whisker reinforced aluminum matrix composites

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Transactions of nonferrous metals Society of China 2020年第7期30卷 1731-1742页

作者： neeraj PAnDEY ICHAKRABARTY Kalpana BARKAnE nSmEHTA mRmAJHI Department of Ceramic Engineering Indian Institute of Technology(BHU)VaranasiU.P.India Department of metallurgical Engineering Indian Institute of Technology(BHU)VaranasiU.P.India

The microstructural features and the consequent mechanical properties were characterized in aluminium borate whisker(ABOw)(5, 10 and 15 wt.%) reinforced commercially-pure aluminium composites fabricated by conventional powder metallurgy technique. The aluminium powder and the whisker were effectively blended by a semi-powder metallurgy method. The blended powder mixtures were cold compacted and sintered at 600 ℃. The sintered composites were characterized for microstructural features by optical microscopy(om), scanning electron microscopy(SEm), energy dispersive spectroscopy(EDS), transmission electron microscopy(TEm) and X-ray diffraction(XRD) analysis. Porosity in the composites with variation in ABOw contents was determined. The effect of variation in content of ABOw on mechanical properties, viz. hardness, bending strength and compressive strength of the composites was evaluated. The dry sliding wear behaviour was evaluated at varying sliding distance at constant loads. maximum flexural strength of 172 mPa and compressive strength of 324 mPa with improved hardness around HV 40.2 are obtained in composite with 10 wt.% ABOw. Further increase in ABOw content deteriorates the properties. A substantial increase in wear resistance is also observed with 10 wt.% ABOw. The excellent combination of mechanical properties of Al-10 wt.%ABOw composites is attributed to good interfacial bonds, less porosity and uniformity in the microstructure.

关键词： aluminum matrix composite powder metallurgy aluminum borate whisker(ABOw)reinforcement flexural strength compression test dry sliding wear

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microstructure Evolution during Friction Stir Welding of Aluminum Alloy AA2219

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Journal of materials Science & Technology 2010年第8期26卷 747-753页

作者： K.S.Arora S.Pandey m.Schaper R.Kumar mechanical Engineering Department Indian Institute of Technology Institut fuer Werkstoffwissenschaft Technische Universitaet Dresden Institut fuer Sicherheitsforschung Forschungszentrum Dresden-Rossendorf Engineering Division National Metallurgical Laboratory

The characterization of microstructure evolution in friction stir welded aluminum alloy was carried out by optical microscopy （om） and transmission electron microscopy （TEm） and electron backscatter diffraction （EBSD）. The weld nugget consisted of very fine equiaxed grains and experienced dissolution of nearly half of metastable precipitates into the matrix during welding. Thermomechanically affected zone （TmAZ） also experienced dissolution of precipitates but to a lesser extent whereas coarsening of precipitates was observed in heat affected zone （HAZ）. Grain boundary misorientation measurements using EBSD indicated continuous dynamic recrystallization as the underlying mechanism for the fine equiaxed nugget grains. The yield and tensile strength of the weld decreased with comparison to base material. But due to the decrease of grain size and the dissolution of second phase precipitates, an increased Charpy energy value was observed in the weld n u gget.

关键词： Friction stir welding AA2219 Precipitates Vickers hardness Tensile testing Charpy impact energy

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Application of nejayote as a Foliar and Edaphic Fertiliser to native Blue maize (Zea mays L.) Crops

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american Journal of Plant Sciences 2016年第15期7卷 2221-2238页

作者： Victoria Téllez Jesús F. López Agustín Aragón Teresa Zayas Posgrado en manejo Sostenible de Agroecosistemas BUAP Puebla México Centro de Agroecología BUAP Puebla México Posgrado en Ciencias ambientales Instituto de Ciencias Benemérita Universidad Autónoma de Puebla (BUAP) Puebla México

Raw and treated “nejayote” were assessed as foliar and edaphic fertilisers for native blue maize (Zea mays L.) crops in the municipality of amozoc de mota, Puebla, mexico, during the 2015 agricultural cycle. Treated nejayote refers to raw nejayote subjected to a coagulation-flocculation process. Two states of nejayote were established (raw and treated nejayote) with different physicochemical properties. Foliar bio-fertilisers were prepared from raw and treated nejayote and mixed with organic matter (om) to promote a fermentation process. The foliar treatments used were: BnC5, BnC15, BnC30 (raw nejayote-based bio-fertiliser at 5%, 15%, and 30%), BnCQ5, and nCQ30 (nejayote treated by chemical coagulation at 5% and 30%), with BT as a control (traditional bio-fertiliser). The edaphic treatments used were: nC50, nC75, and nC100 (raw nejayote at 50%, 75%, 100%), with AP as a control (drinking water), thus giving rise to 10 treatments in terms of content of raw or treated nejayote. Foliar and edaphic field treatments applied to native blue maize crops were statistically assessed using the following response variables: plant height, stem diameter, number of leaves, and grain yield. The experiment was laid out in a randomised complete block design (RCBD) with five replications of each treatment. The results obtained showed, that foliar or edaphic application at the different stages of development did not produce statistically significant differences, at P ≤ 0.05, in terms of response variables. The most significant effects occurred at the early stage of plant development and were mainly reflected in the stem diameter with foliar treatment nCQ30 and in the number of leaves with foliar treatment BnC5. At the final stage of crop development, the highest yield (0.639 ± 0.121 t·ha-1) was obtained with treatment BnC5, which produced a statistically significant difference (b) in relation to the rest of the foliar and edaphic treatments (Tukey P ≤ 0.05).

关键词： maize Crop Foliar-Edaphic Fertiliser Raw nejayote Treated nejayote

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Characterization of cooling rate and microstructure of Cu Sn melt droplet in drop on demand process

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Transactions of nonferrous metals Society of China 2017年第7期27卷 1636-1644页

作者： Yi XU n. ELLEnDT Xing-gang LI V. UHLEnWInKEL U. FRITSCHInG School of materials Science and Engineering Southwest Jiaotong University Chengdu 610031 China Foundation Institute of materials Science Bremen University Bremen 28359 Germany

Different sized single droplets of Cu-6%Sn alloy were prepared by drop on demand(DOD)*** secondarydendrite arm spacing was measured and correlated with the droplet cooling rate by a semi-empirical *** microstructure ofdroplets was observed by optical microscopy(om)and electro backscatter diffraction(EBSD).The dendrite feature of singledroplets depends on solidification rate,cooling medium and flight *** droplets collide with each other at temperaturesbetween solidus and liquidus,the dendrites and grains are refined obviously possibly because the collision enhances the heat *** cooling rate of colliding droplets is estimated to be more than4×104K/s based on a newton’s cooling *** dendritesgrow along the colliding direction because of the temperature gradient induced by the internal flow inside the droplets.

关键词： impinging droplet secondary dendrite arm spacing cooling rate heat transfer drop on demand

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Sources and dynamics of sedimentary organic matter in Sundarban mangrove estuary from Indo-Gangetic delta

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Ecological Processes 2017年第1期6卷 69-83页

作者： m.Bala Krishna Prasad Alok Kumar A.L.Ram.nathan Dilip Kumar Datta 22616 Shining Harness Street ClarksburgMD 20871USA School of Environmental Sciences Jawaharlal Nehru UniversityNew Delhi 110067India Environmental Science Discipline Khulna UniversityKhulna 9208Bangladesh

Introduction:mangrove forests are highly productive ecosystems distributed along the tropical coast *** biogeochemistry of mangroves are primarly driven by both allochthonous and autochthonous *** of organic matter in coastal ecosystems enables to understand the biogeochemical transformation of organic matter and its influence on ecosystem productivity in response to various changing environmental ***,the elemental and stable carbon and nitrogen levels were employed to understand the organic matter(om)dynamics in the Sundarban mangrove ecosystem(India-Bangladesh).Results:Differences in stable isotope values indicate that variable sources influence the om dynamics in Sundarban *** progressive enrichment inδ13C levels along the land-coastal continuum indicates that the terrestrial and marine inputs are dominant at the landward and seaward ends,*** CuO oxidationderived lignin phenol monomers describe significant levels of total lignin are preserved in Sundarban mangrove sediments during *** phenol monomer ratios are lower than the plant litter explaining that aromatic ring cleavage is the dominant mechanism for the lignin ***,the ad/Al ratios were higher than the plant litter explaining the oxidation of propyl side chain of vascular om influencing the carbon cycling in Sundarban ***,the ad/Al ratios describe the vascular om degradation is through the oxidation of propyl side ***:The regional variability in land-use regulates the spatial variability in C,n,OC/Tn ratio,δ13C andδ15n between the Indian and the Bangladesh Sundarban mangroves and indicates that in the upstream terrestrial organic matter and/or mangrove plant litter contribute significant amount of organic matter,whereas the marine POC influences the organic matter dynamics in *** three end-member mixing model applying terrestrial plant litter,seston,and marine POC as e

关键词： Sundarban mangrove Organic carbon Stable isotopes Lignin phenols Three end-member mixing model

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Influence of mg addition and T6 heat treatment on microstructure,mechanical and tribological properties of Al-12Si-3Cu based alloy

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Transactions of nonferrous metals Society of China 2021年第8期31卷 2208-2219页

作者： m.BEDER Y.ALEmDAG Department of mechanical Engineering Gumushane UniversityGumushaneTurkey Department of mechanical Engineering Karadeniz Technical UniversityTrabzonTurkey

The aim of the present study was to investigate the influence of mg addition and T6 heat treatment on microstructure,mechanical and tribological properties of the Al-Si-Cu-mg *** this context,a series of Al-12Si-3Cu-(0.5-2.5)mg(wt.%)alloys were produced by permanent mould casting,and then subjected to T6 *** microstructure and mechanical properties were investigated using om,XRD,SEm,EDS along with hardness,tension,compression and Charpy impact *** sliding friction and wear properties of the alloys were studied using a ball-on-disk type *** was observed that the microstructure of as-cast Al-12Si-3 Cu-mg alloys consisted of a(Al),Si,O-CuAb,0-mg_(2)Si,0-Abmg_(8)Cu(2)Si_(6) and π-Ahmg_(3)FeSi_(6) phases.T6 heat treatment gave rise to nearly spherodization of eutectic Si particles,formation of finer 0-CuAH and 0-mg_(2)Si precipitates and elimination of Chinese script morphology of 0-mg_(2)Si *** addition of mg up to 2.5 wt.%decreased the hardness,tensile and compressive strengths,tensile elongation and impact toughness of the as-cast and T6-treated alloys and increased their friction coefficient and volume loss.T6 treatment,on the other hand,led to a significant increase in mechanical properties and wear resistance of as-cast alloys.

关键词： Al-Si-Cu alloys mg content T6 treatment microstructure mechanical properties wear properties fracture surface

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PRECIPITATIOn BEHAVIOR OF m_(2)n In A HIGH-nITROGEn AUSTEnITIC STAInLESS STEEL DURInG ISOTHERmAL AGInG

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Acta metallurgica Sinica(English Letters) 2007年第2期20卷 95-101页

作者： F. Shi L.J. Wang W.F. Cui C.m. Liu School of materials ＆ metallurgy Northeastern UniversityShenyang 110004 China

The precipitation behavior of m2n and the microstructural evolution in a Cr-mn austenitic stainless steel with a high nitrogen content of 0.43mass% during isothermal aging has been investigated using optical microscopy （ om）, scanning electron microscopy （SEm）, and transmission electron microscopy （TEm）. The aging treatments have led to the decomposition of nitrogen supersaturated austenitic matrix through discontinuous cellular precipitation. The precipitated cells comprise alternate lamellae of m2n precipitate and austenitic matrix. This kind of precipitate morphology is similar to that of pearlite. However, owing to the non-eutectoidic mechanism of the reaction, the growth characteristic of the cellular precipitates is different from that of pearlite in Fe-C binary alloys. m2n precipitate in the cell possesses a hexagonal crystal structure with the parameters a = 0.4752nm and c = 0.4429nm, and the orientation relationship between the m2V precipitates and austenite determined from the SadP is [01^-10]m2n//[101]γ, [2^-1^-10]m2n//[010]γ.

关键词： austenitic stainless steel high nitrogen microstructureisothermal aging precipitation

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