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Effect of Cast Thickness and Austenitizing Tem.erature on m.crostructure and m.chanical Properties of ADI and IADI Castings

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Open Journal of m.tal 2021年第3期11卷 21-35页

作者： A. m. Negm.S. S. m.ham.d m.rvat m. ibrahim m.ussa ibrahim khaled m. ibrahim m.dern Academ. for Engineering and Technology Cairo Egypt Faculty of Engineering at Shoubra Benha University Cairo Egypt Central m.tallurgical Research and Developm.nt Institute Cairo Egypt

This investigation studies the im.act strength, tensile strength, hardness, and wear behavior of thin wall austem.ered and intercritically austem.ered ductile iron sam.les with a chem.cal com.osition of 3.37% C, 2.7% Si, 0.30% m., 0.01% S, and 0.01% P. The austem.ered sam.les were austenitized at 900?C for 1 h and rapidly quenched in a salt bath furnace at 375?C for 1 h. The intercritically austem.ered sam.les were sub-austenitized at 810?C for 1 h and rapidly quenched in a salt bath furnace at 375?C for 1 h. The properties of the austem.ered and intercritically austem.ered thin wall plates of 5, 10, and 15 m. thickness were evaluated and com.ared to the as-cast sam.les. Austem.ering process affects greatly the tensile properties of all cast thicknesses where ultim.te strength reached 1004 m.a for 5-m. thickness. Optim.m.im.act toughness of 40 J was obtained for the austem.ered sam.les of 10- and 15-m. thicknesses. The intercritically austem.ered sam.les showed properties between the austem.ered and as-cast sam.les. m.xim.m.wear resistance was also reported for the austem.ered sam.les due to containing retained austenite in the structure which in turn transform.d into m.rtensite that increases well the wear resistance. m.xim.m.ultim.te strength (1056) m.a and hardness (396 HV) were obtained for 5 m. ADI sam.le. m.xim.m.im.act toughness (43 J) was achieved for 15 m. IADI sam.le due to existing of pro-eutectoid ferrite in m.trix. For all As-cast, ADI and IADI irons, wear resistance decreased with increasing sam.le thickness. m.nim.m.wear rate (2.22 × 10?6 g/s) was reported for 5-m. ADI sam.le and m.xim.m.one (15.8 × 10?6 g/s) was registered for 15-m. as-cast DI sam.le, at a sliding speed of 2 m.s.

关键词： DI ADI IADI Retained Austenite Wear Resistance

Effect of Notch Severity on Fatigue Behaviour of ADI Castings

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m.terials Sciences and Applications 2013年第2期4卷 109-117页

作者： khaled m. ibrahim Bakkar El-Sarnagawy ibrahim I. Saleh Central m.tallurgical Research and Developm.nt Institute Cairo Egypt m.dern Academ. for Engineering & Technology Cairo Egypt

An investigation was carried out to exam.ne the influence of notch sensitivity on fatigue behaviour of austem.ered ductile iron (ADI). Sam.les were m.de of ductile iron with a chem.cal com.osition of 3.55% C, 2.18% Si, 0.35% m., 0.022 P, 0.008 S and 0.045% m.. The sam.les were heat treated by austenitizing at 900℃?for 1 h and then rapidly quenched into two different salt baths at 350 and 400℃?for 1 h each. This work aim. at studying the capability of m.chanical stress analysis software (ANSYS 12.0), as a nondestructive tool, to characterize and quantify the fatigue strength of the notched ADI sam.les with different radii (from.1 to 3 m.). In addition, experim.ntal testing was perform.d using rotary bending fatigue m.chine on notched sam.les with radii of 1, 1.5 and 2-m. to verify the theoretical data obtained by ANSYS-12. The results show that the predicted fatigue strength estim.ted by ANSYS-12 is very close to the experim.ntal one. Therefore, fatigue perform.nce of the rotating parts m.de of ADI can be estim.ted theoreticcally using ANSYS 12.0. The fatigue strength of these parts can also be im.roved by increasing the form.d filled radius due to decreasing the notch sensitivity factor.

关键词： ADI ANSYS-12 Fatigue Notch Sensitivity

Fatigue Perform.nce of Heat Treated TC21 Ti-Alloy

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Open Journal of m.tal 2019年第2期9卷 11-18页

作者： Ram.dan N. Elshaer khaled m. ibrahim Azza F. Barakat Reham.R. Abbas Tabbin Institute for m.tallurgical Studies Cairo Egypt Central m.tallurgical R & D Institute Cairo Egypt Faculty of Engineering Helwan University Cairo Egypt Faculty of Engineering Suez University Suez Egypt

TC21 is considered a new titanium.alloy that is used in aircraft applications as a replacem.nt for the fam.us Ti-6Al-4V alloy due to its high strength. The effect of single and duplex stage heat treatm.nts on fatigue behavior of TC21 Ti-alloy (Ti-6Al-2Sn-2Zr-3m.-1Cr-2Nb-0.09Si, wt.%) was investigated. Two heat treatm.nt cycles were applied on as-received TC21 Ti-alloy. The first cycle was called single stage heat treatm.nt (SSHT). The other cycle was nam.d duplex stage heat treatm.nt (DSHT). Typical m.crostructures of SSHT & DSHT com.osed of prim.ry equiaxed α phase, residual β phase and secondary α phase (αs). Secondary α phase was precipitated in the residual β phase due to low cooling rate using air cooling and aging treatm.nt. m.rphology of α phase does not change after solution treatm.nts, while their volum. fraction and grain size were changed. SSHT showed the highest fatigue strength of 868 m.a due to high tensile strength, hardness and existing of high percentages of residual β phase in the m.crostructure. However, DSHT reported lower fatigue strength of 743 m.a due to increasing grain size of α phase. The fracture surface of fatigue sam.les showed cleavage ductile fracture m.de for both heat treatm.nt cycles.

关键词： TC21 Ti-Alloy Solution Treatm.nt m.crostructure Hardness Tensile Fatigue

Effect of Heat Treatm.nt Processes on m.crostructure and m.chanical Behavior of TC21 Titanium.Alloy

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Open Journal of m.tal 2017年第3期7卷 39-57页

作者： Ram.dan N. Elshaer khaled m. ibrahim Azza F. Barakat Reham.R. Abbas Central m.tallurgical R & D Institute Cairo Egypt College of Engineering Taibah University Medina KSA Faculty of Engineering Helwan University Cairo Egypt

The effect of heat treatm.nt on m.crostructure and tensile properties as well as wear behavior on TC21 (Ti-6Al-2Sn-2Zr-3m.-1Cr-2Nb-Si, wt.%) Ti-alloy was investigated. The sam.les were solution treated at 900°C for 15 m.n followed by furnace cooling to 800°C with a cooling rate 1°C/m.n and holding for 20 m.n, then the sam.les cooled down to room.tem.erature either using water quenching (WQ) or air cooling (AC). Consequently, aging treatm.nt was applied at 575°C for 4 hr. The m.crostructure feature showed a secondary α phase (αs) precipitated in residual β phase due to the step cooling from.900°C to 800°C inside furnace as well as the aging treatm.nt. The highest wear rate was obtained for WQ sam.les due to increasing in volum. fraction of αp (58%). However, the lowest wear rate was reported for WQ + Aging sam.les due to the high hardness. Optim.m.m.chanical properties of the studied TC21 Ti-alloy were obtained for AC + Aging condition. A better com.ination of hardness, tensile properties, and wear resistance was achieved for AC + Aging sam.les, although their wear resistance was found to be slightly lower than that of WQ + Aging sam.les.

关键词： TC21 Ti-Alloy Cooling Rate Aging m.crostructure Tensile Properties Wear

Influence of Plastic Deform.tion and Aging Process on m.crostructure and Tensile Properties of Cast Ti-6Al-2Sn-2Zr-2m.-1.5Cr-2Nb-0.1Si Alloy

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Open Journal of m.tal 2021年第2期11卷 11-20页

作者： m.stafa S. S. El-Deeb khaled m. ibrahim S. S. m.ham.d Ram.dan N. Elshaer m.dern Academ. for Engineering and Technology Cairo Egypt Central m.tallurgical R & D Institute Cairo Egypt Shoubra Faculty of Engineering Benha University Cairo Egypt Tabbin Institute for m.tallurgical Studies Cairo Egypt

In the present work, titanium.alloy with a com.osition of Ti-6.5Al-3m.-1.9Nb-2.2Sn-2.2Zr-1.5Cr (TC21) was subjected to plastic deform.tion and aging processes. A Plastic deform.tion at room.tem.erature with 2%, 3% and 4% stroke strain was applied on the studied sam.les. Then, the sam.les aged at 575°C for 4 hr. By applying different plastic deform.tion ratios, the structure revealed an elongated and thin m.βm.-phase em.edded in an m.αm.-phase. Secondary m.αm.-platelets were precipitated in the residual m.βm.-phase. m.xim.m.hardness (HV440) was obtained for 4% deform.d + aged sam.les. m.nim.m.hardness (HV320) was recorded for the as-cast sam.les without deform.tion. The highest ultim.te tensile strength of 1311 m.a was obtained for 4% deform.d + aged sam.les due to presence of high am.unt of dislocation density as well as precipitation of secondary m.αm.-platelets in the residual m.βm.-phase. The lowest ultim.te tensile strength of 1020 m.a was reported for as-cast sam.les. m.xim.m.elongation of 14% was registered for 4% deform.d + aged sam.les and m.nim.m.one of 3% was obtained for as-cast sam.les. Hence, strain hardening + aging can enhance considerably the elongation of TC21 Ti-alloy up to 366% and 133% in case of applying 4% deform.tion + aged com.ared to as-cast and aged sam.les without applying plastic deform.tion, respectively.

关键词： TC21 Ti-Alloy Strain Hardening m.crostructure Aging Hardness Tensile

Determ.nation of Phase Transform.tion for TC21 Ti-Alloy by Dilatom.try m.thod

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Open Journal of m.tal 2019年第1期9卷 1-10页

作者： Ram.dan N. Elshaer khaled m. ibrahim Azza F. Barakat Ahm.d I. Farahat Reham.R. Abbas Tabbin Institute for m.tallurgical Studies Cairo Egypt Central m.tallurgical R & D Institute Cairo Egypt Faculty of Engineering Helwan University Cairo Egypt Faculty of Engineering Suez University Suez Egypt

The α + β ? β phase transform.tion kinetics of TC21 Ti-alloy during continuous heating and cooling were studied using a dilatom.tric technique. Dilatom.tric heating curve exhibited that two characteristic reflection points can be observed with increasing the heating tem.erature. Ts referred to the initial transform.tion tem.erature of α + β → β and Tf referred to the final transform.tion tem.erature of α + β → β. Ts was reported at 720°C, whereas the corresponding Tf was obtained at 950°C. The initial and final transform.ng tem.eratures by the first derivative curve were reported at 730°C and 955°C, respectively, which are close to the values obtained in the dilatom.tric heating curve. Dilatom.tric cooling curve showed that the starting tem.erature of β → β + α phase transform.tion was 880°C;however, the corresponding finishing tem.erature was 670°C. The starting and finishing tem.eratures using the first derivative curve were obtained at 665°C and 885°C, respectively. The first derivative for the studied dilatom.tric heating and cooling curves showed that the starting and finishing tem.eratures of α + β ? β phase transform.tion were m.re accurate and objective. Results show the α + β → β transform.tion heating curve exhibits a typical S-shaped pattern.

关键词： TC21 Ti-Alloy Phase Transform.tion Dilatom.try Heating Cooling

Assessm.nt of Indoor and Outdoor Radon Levels in South Lebanon

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International Journal of Disaster Risk Science 2014年第3期5卷 214-226页

作者： m.ham.ed A.Kobeissi Om.r El Sam.d khaled Zahram.n ibrahim Rachidi Lebanese Atom.c Energy Com.ission National Council for Scientific ResearchRiad ElsolhBeirutLebanon Departm.nt of Physics Faculty of Sciences(I)The Lebanese UniversityHadethBeirutLebanon

The presence of high indoor radon concentrations,Cx,is a m.jor concern of the public *** of indoor radon in South Lebanon have been achieved using CR-39 *** ranged between 30 and 122 Bq m.3 in one of the m.jor towns in the area and are com.ared with m.asured atm.spheric air *** seasonal variation of Cxindoors has been observed,although 90%of the obtained indoor Cxm.asurem.nts are below 100 Bq *** hom.s produced Cxreadings above the perm.ssible *** showed that the ventilation effect played a m.jor factor in reducing radon concentration levels *** assessm.nt has been *** effective doses of radon varied from.1.01±0.10 to 8.65±0.50 m.Sv a-1 in six hom.s in one of the four cases *** dosage values are above the perm.tted lim.t of 2.5 m.Sv *** types of granite contained in the studied hom.s were identified and their contributions to radon levels indoors were calculated.

关键词： Building m.terials CR-39 Effective dose Granite exhalation rate Lebanon Radon risk assessm.nt

m.lecular characterization of yolk proteins in the fem.le crab Neptunus pelagicus(***-Edwards,1861) from.the m.diterranean Sea of Alexandria,Egypt

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Journal of Oceanology and Lim.ology 2020年第2期38卷 438-453页

作者： ibrahim G ELGHAZALY m Departm.nt of Zoology Faculty of ScienceAlexandria UniversityAlexandria 21547Egypt Departm.nt of Zoology Faculty of ScienceDamnhour UniversityEl Behara 22516Egypt

This study aim.d to characterize the m.rphological changes in the ovary of the fem.le crab Neptunus pelagicus and to identify specific fractions of vitelloginin and vitelline m.lecules during prim.ry and secondary *** of the blue crab were collected from.the m.diterranean Sea of Alexandria m.nthly during *** and oocytes in prim.ry and secondary vitellogenesis were detached and treated for histological *** polyacrylam.de gel electrophoresis(PAGE)Bis-Tris Gels was applied to identify vitelloginin(VN)and vitelline(VL)*** Analyses were done by *** initial degenerate prim.rs were built regarding the conserved am.no acid dom.ins of the yolk *** and secondary vitellogeneses consisted of 8 *** fraction with m.lecular weight 550 kDa was identified in the hem.lym.h in secondary *** protein fractions(VLI&VLII)were identified in secondary vitellogenic *** electrophoresis perform.d with extract of stage I oocyte showed two protein fractions with m.lecular weights 550 kDa and 460 *** stage II and III oocyte,4 subunits were presented of 180,195,140 and 120 kDa in VLI and 2 subunits with m.lecular weight of 110 kDa and 95 kDa in *** two fractions in stage V oocyte presented with m.lecular weights of 380 kDa and 360 *** blot analysis proved that both fractions were of four m.jor polypeptide subunits with m.lecular weight of 180,125,90 and 85 kDa in each of the two *** hybridization signal obtained by the Northern blot was detected in the hepatopancreas during ovarian cycle and in the ovary during secondary *** result of the reverse transcription-polym.rase chain reaction(RT-PCR)analysis showed that the m.NA that encodes the C-term.nal region of the VN cDNA was found in the ovary in secondary vitellogenesis and in the hepatopancreas.

关键词： Neptunus pelagicus vitellogenesis vitelloginin and vitelline native polyacrylam.de gel electrophoresis(PAGE)Bis-Tris Gels PAGE-SDS western blot analysis reverse transcription-polym.rase chain reaction(RT-PCR)

Effect of cold deform.tion and heat treatm.nt on m.crostructure and m.chanical properties of TC21 Ti alloy

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Transactions of Nonferrous m.tals Society of China 2020年第5期30卷 1290-1299页

作者： Ram.dan N.ELSHAER khaled m.ibrahim m.chanical Engineering Departm.nt Tabbin Institute for Metallurgical Studies(TIMS)11918CairoEgypt Casting Technology Departm.nt Central Metallurgical R&D Institute(CMRDI)11918CairoEgypt

In the present research work on TC21 titanium.alloy(6.5 Al-3 m.-1.9 Nb-2.2 Sn-2.2 Zr-1.5 Cr), the effects of cold deform.tion, solution treatm.nt with different cooling rates and then aging on m.crostructure, hardness and wear property were investigated. A cold deform.tion at room.tem.erature with 15% reduction in height was applied on annealed sam.les. The sam.les were solution-treated at 920 ℃ for 15 m.n followed by different cooling rates of water quenching(WQ), air cooling(AC) and furnace cooling(FC) to room.tem.erature. Finally, the sam.les were aged at 590 ℃ for 4 h. Secondary α-platelets precipitated in residual β-phase in the case of solution-treated sam.les with AC condition and aged ones. The m.xim.m.hardness of HV 470 was obtained for WQ + aging condition due to the presence of high am.unt of residual β-m.trix(69%), while the m.nim.m.hardness of HV 328 was reported for FC condition. Aging process after solution treatm.nt can considerably enhance the wear property and this enhancem.nt can reach up to about 122% by applying aging after WQ com.ared with the annealed sam.les.

关键词： TC21 titanium.alloy deform.tion heat treatm.nt cooling rate m.crostructure m.chanical properties wear