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Taguchi optimization of process parameters in friction stir processing of pure mg

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Journal of magnesium and Alloys 2015年第2期3卷 168-172页

作者： D.Ahmadkhaniha m.heydarzadeh sohi A.Zarei-Hanzaki S.m.Bayazid m.Saba School of metallurgy and materials College of EngineeringUniversity ofTehranPO Box 1155-4563TehranIran

Taguchi experimental design technique was applied to determine the most influential controlling parameters of FSP such as tool rotational speed,travel speed,tilt angle and penetration depth on hardness value of *** this case,9 combinations of these 4 essential processing parameters were set and Taguchi's method followed *** to noise ratio(S/N)analysis showed that maximum hardness achieved when rotational and travel speeds,penetration depth and tilt angel were chosen as 1600 rpm,63 mm/min,0.1 mm and 2°,*** addition,analysis of variance(ANOVA)technique indicated that tilt angle and rotational as well as travel speed are the significant influential parameters in the hardness value of the treated samples,*** a model for hardness values based on FSP parameters was calculated by design expert which was also confirmed by experimental results.

关键词： mg FSP Hardness Taguchi ANOVA Design-expert

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未热解厚热障涂层的隔热能力和黏接强度

Transactions of Nonferrous metals Society of China 2024年第4期34卷 1226-1236页

作者： mohammad IZADINIA Reza SOLTANI mahmoud heydarzadeh sohi Javad mOSTAGHImI School of metallurgy and materials Engineering College of EngineeringUniversity of TehranTehranIran Centre for Advanced Coating Technologies Department of Mechanical and Industrial EngineeringUniversity of TorontoTorontoOntarioCanada

对比研究使用未热解粉末制备的厚热障涂层(UPTTBC)和传统TBC、厚TBC(TTBC)及密集垂直裂纹(DVC)TTBC 4种涂层的隔热能力和黏接强度。采用降温法测试涂层的隔热能力;根据ASTm C633标准,采用拉拔试验检测涂层的黏接强度。结果显示,UPTTBC和... 详细信息

对比研究使用未热解粉末制备的厚热障涂层(UPTTBC)和传统TBC、厚TBC(TTBC)及密集垂直裂纹(DVC)TTBC 4种涂层的隔热能力和黏接强度。采用降温法测试涂层的隔热能力;根据ASTm C633标准,采用拉拔试验检测涂层的黏接强度。结果显示,UPTTBC和DVC TTBC的黏接强度分别比TTBC高35%和25%。这可能是由于UPTTBC结构中存在亚微米尺度的未熔化区域,起到了阻止裂纹扩展的作用。此外,隔热测试的结果表明,DVCTTBC涂层的隔热能力最差,为0.28℃/μm,而UPTTBC涂层的隔热能力最强,为0.40℃/μm。由于UPTTBCs显微组织中存在亚微米区域,使涂层展现出优越的隔热能力。相反,DVCTTBC因其致密的结构,具有最低的隔热能力。

关键词：厚热障涂层密集垂直裂纹热障涂层未热解粉末黏接强度隔热能力

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Effects of TIG Surface melting and Chromium Surface Alloying on microstructure, Hardness and Wear Resistance of ADI

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Journal of Iron and Steel Research International 2008年第4期15卷 86-94页

作者： A Amirsadeghi m.heydarzadeh sohi S F Kashani Bozorg School of metallurgy and materials Engineering University of Tehran Tehran Iran

microhardness and wear resistance of different rnicrostructures formed by TIG （tungsten inert gas） surface melting and chromium surface alloying （using ferrochromium） of ADI （austempered ductile iron） were studied. Surface melting resulted in the formation of a ledeburitic structure in the melted zone, and this structure has a hardness up to 896 HV as compared to 360 HV in that of ADI. moreover, chromium surface alloying resulted in the formation of different structures including：（1） a hypereutectic structure consisting of primary （Fe,Cr）7C3 carbides and a eutectic matrix of transformed austenite （into martensite and retained austenite）, as also （Fe,Cr）7C3 carbides, with a hardness of 1078 HV; （2） a hypoeutectic structure consisting of the same eutectic along with transformed primary austenite, with a hardness of 755 HV; and （3） a ledeburitic structure with an acicular morphology and a hardness of 896 HV. The results also indicated that surface melting reduced the wear rate of the ADI by approximately 37%. Also, chromium surface alloying yielded a superior wear behavior and reduced the wear rate of the treated specimens by about 38% and 70%, depending on the structures formed.

关键词： ductile iron surface alloying surface melting chromium wear resistance

The Study of the Grit-blasting Parameters and Their Effects on the Adhesive Strength of the Plasma Sprayed Coatings

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厦门大学学报（自然科学版） 2002年第S1期41卷 108-109页

作者： m.heydarzadeh sohi m Frooghieh Sh Khameneh Asl Dept. of metallurgy and materials Engineering Faculty of Engineering University of TehranDept. of Metallurgy and Materials Engineering Faculty of EngineeringUniversity of TehranDept. of Metallurgy and Materials Engineering Faculty of Engineering University of Tehran IranIranIran

Surface Preparation is very important in adhesive b on ding of spray coatings to the surface of a work piece. The common practice is gr it-blasting of the surface before subjecting it to the spray coating process. In this study, grit-blasting of an AISI 4130 steel (of different heat treatmen ts) with Al 2O 3 particles was studied. Various grit-blasting parameters such as blasting particle size, the distance between blasting nozzle and the work pi ece (25, 30 and 40 cm.), blasting pressure (3,4,5,6 and 7 bars), blasting time ( 3, 6 and 10 seconds), and the blasting angle (45° and 90°) were examined in or der to find the optimum roughness. The mean roughness (Ra) of the grit-blasted surfaces were measured and the vari ations of the roughness with respect to the above mentioned variables were studi ed. The results show that by increasing blasting time, surface roughness increas es up to a maximum and then slightly decreases it with further duration of t he process. On the other hand a lengthy blasting causes some undesirable results such as an increase in residual particles between surface irregularities. There fore an optimum blasting time is of great importance. Increasing the blasting pr essure also provides a rougher surface, but in grit blasting of harder specimens the surface roughness decreases when the pressure reaches a certain limit. About the blasting angle, it was noticed that an angle of 45° results in less r esidual particles between the surface irregularities, in comparison to the angle of 90°. After grit-blasting, the specimens were plasma spray coated with 80% ZrO 2-20 % Y 2O 3 powder. The adhesive strength of the coating to the substrate was the n measured according to the DIN 50160 standard. The results show that for a certain base metal, the adhesive strength is directl y related to the surface roughness of the base material. Residual particles afte r grit-blasting the surface of the specimens can also have a strong deteriorati ng effect on adhesive

关键词： The Study of the Grit-blasting Parameters and Their Effects on the Adhesive Strength of the Plasma Sprayed Coatings

Influence of friction stir processing conditions on corrosion behavior of AZ31B magnesium alloy

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Journal of magnesium and Alloys 2019年第4期7卷 605-616页

作者： Hamed Seifiyan mahmoud heydarzadeh sohi mohammad Ansari Donya Ahmadkhaniha mohsen Saremi School of metallurgy and materials Engineering College of EngineeringUniversity of TehranIran Department of mechanical and mechatronics Engineering University of WaterlooCanada Department of materials and manufacturing Jonkoping UniversitySweden

The present study aims to investigate the effect of friction stir processing(FSP)conditions on the corrosion characteristic of AZ31B magnesium *** made of AZ31B alloy were friction stir processed under various processing conditions,and their microstructure and corrosion behavior were *** corrosion behavior was studied by potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),and immersion test in 3.5%sodium chloride(NaCl)*** results showed a substantial improvement in the corrosion resistance of the friction stir processed AZ31B *** improvement is likely a result of more stable corrosion products and microstructure refinement formed after friction sir processing.

关键词： magnesium Friction stir processing Corrosion Polarization EIS

Effect of Al substitution on phase evolution in synthesized mg_(2)Cu nanoparticles

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International Journal of minerals,metallurgy and materials 2023年第1期30卷 63-71页

作者： Elham mohseni-sohi Farshid Kashani Bozorg School of metallurgy and materials Engineering College of EngineeringUniversity of TehranTehranPO Box 11155/4563Iran

The effect of mg replacement with Al on the discharge capacity of mg_(2)Cu powder mixture was *** mixture of nano-crystalline powder was prepared via mechanical alloying(mA)technique with a high energy planetary ball *** addition,different moles of Al(0.05,0.1,0.15,0.2,and 0.3 m)were substituted to mg_(2)Cu powder.X-ray diffraction(XRD),scanning electron microscopy(SEm),and transmission electron microscopy(TEm)were used to analyze changes in structure,morphology,and grain *** obtained powder was utilized as an anode in a nickel-metal hydride battery(Ni-mH).In the specimens with 0.05 m Al content,the orthorhombic structure of mg_(2)Cu is emerged after 5 h *** results reveal that more than 0.1 m Al substitution leads to an appearance of mgCu_(2) *** substi-tution does not affect microstructure uniformity;however,it causes a decrease in crystalline size and lattice *** selected area diffraction(SAD)pattern elucidates that the electrode with the mg_(1.9)Al_(0.1)Cu chemical composition and 20 h milling has the maximum discharge capacity.

关键词： mg_(2)Cu mechanical alloying nanocrystalline discharge capacity