توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Transient Liquid Phase Diffusion Bonding of Al A356\SiC Metal Matrix Composite Using Cu interlayer
نویسنده(ها): ، ،
اطلاعات انتشار: دومین کنفرانس بین المللی کامپوزیت، سال
تعداد صفحات: ۶
SiCp reinforced aluminum metal matrix composites (SiCp\Al MMCs) have a unique combination of mechanical and physical properties, such as high specific strength and specific modulus of elasticity, low thermal expansion coefficient and good wear resistance. They are widely used in aerospace engineering, automotive industry, electronic packaging and medical appliances. Suitable joining technologies will be required if the materials are to be used as structural components. Therefore, transient liquid phase diffusion bonding of Al A356\SiC metal matrix composite using Cu interlayer at 560 and 580<\div>

۲Investigation on Microstructure of Transient Liquid Phase Diffusion Bonded Joints of Al\Mg2Si Metal Matrix Composite
نویسنده(ها): ، ،
اطلاعات انتشار: دومین کنفرانس بین المللی کامپوزیت، سال
تعداد صفحات: ۶
The growing demand for more fuel–efficient vehicles to reduce energy consumption and air pollution is a challenge for the automotive industry. Recently, Al–Mg2Si metal matrix composites (MMCs) have been developed for high–performance applications in automotive industries. Al– and Mg–based composites, reinforced with particulates of Mg2Si have been recently introduced as a new group of particulate metal matrix composites that are good candidates to replace Al–Si alloys used in aerospace and engine applications. Suitable joining technologies will be required if the materials are to be used as structural components. As–cast Al\Mg2Si metal matrix composite was joined by transient liquid phase diffusion bonding using Cu interlayer at various bonding temperatures and durations. This metal matrix composite containing 15 wt% Mg2Si was produced through in situ technique by gravity casting. Specific diffusion bonding process was applied as a low vacuum technique. The microstructure of joints was examined by scanning electron microscope equipped with energy dispersive X–ray spectroscopy and optical microscope. The microstructure of joints consisted of Al–α, CuAl2 and Mg2Si or Al–α and Mg2Si depending on bonding temperature and duration. Also, bonding temperature and duration affected aggregation zone of Mg2Si particles at bonded interface.<\div>

۳effect of resistance upset welding parameters on metallurgical sturcture electrical resistivity and tensile strength of heating element 80Ni–20Cr
نویسنده(ها): ، ،
اطلاعات انتشار: کنگره بین المللی جوش و روشهای اتصال، سال
تعداد صفحات: ۷
resistance upset welding is used for joining heating alloy 8i0Ni–20Cr. This process is performed using heat and pressure simultaneously . Acceptable weld be achieved when the resistivity differences betweenwelded and original elemetnts are less than 10 percent and appropriate tensile strength is acquired there are three main parameters in resistance upset welding electrical power applied pressure and welding time in this research effect of these parameters on structure resistivity and fracture strength of 1.6 mm wire elements has been studied results show that increase of welding power leads to change in resistivity less than 10 percent the fracture strength reaches to its maximum first and subsequently decreases due to coarsening of GAZ grains by properly choosing of welding pressure roughness of joining surfaces is lowered and decreases resistivity and its changes results are satisfying .<\div>

۴effect of wire chemical composition on microstructure and mechanical properties of submerged arc–welded API–X70 weld metal
نویسنده(ها): ، ،
اطلاعات انتشار: کنگره بین المللی جوش و روشهای اتصال، سال
تعداد صفحات: ۸
the aim of this research is to investigate the effect of increasing manganese Mn content with or sithout presence of chromium Cr and molybdenum Mo on microstructure and mechanical properties of API–X70 weld metal five different welding wires containing different amount of Mn Cr and Mo were selected submerged arc –welding SAW process was used at practical condition for spiral gas tranmission pipes . the material was 19.8 mm thick HSLA API–X70 pipe line steel microstructural examination results show increase of both the amount and fineness of acicular ferrite and decrease of grain boundary ferrite with increasing of Mn ,Cr and Mo contents in weld metal . mechanical testing results indicate that by increasing Mn content up to 1.66 %wt,yield stress tensile strength hardness and toughness of weld metal are improved.<\div>

۵resistance upset butt welding of 304 austenitic stainless steel
نویسنده(ها): ،
اطلاعات انتشار: کنگره بین المللی جوش و روشهای اتصال، سال
تعداد صفحات: ۷
in this research resistance upset butt RUB welding of 304 austenitic stainless steel and effect of welding power and upset pressure on microstructure and mechanical properties of the joint were investigated microstructure of the weld was studied using scanning electron microscopy x–ray diffraction analysis was used to evaluate the phase s that formed in the joint interface and HAZ . also tensile strength test were performed results showed that there were three different zones in different distances fromthe joint interface and delta ferrite phase has formed in these regions there was no precipitation of chromium carbide in the HAZ.<\div>

۶the effects testing time and temperature of low vacuum diffusion welding on microstructure and mechanical properties of SiCp\A356Al MMC
نویسنده(ها): ، ، ،
اطلاعات انتشار: کنگره بین المللی جوش و روشهای اتصال، سال
تعداد صفحات: ۵
fusion welding brazing diffusion welding and friction welding could be used to weld the reinforced A1 MMC in fusion welding many problems may occur at the vicinity of welding where particularly at the heat affected zone . During the welding of aluminum an oxide film which covers the surface of A1makes the welding difficult therefore vacuum diffusion bonding process is used for investigating joining characteristics of Sic particulate reinforced aluminum metal matrix composites A356\SICP–MMC metal matrix composites contain 10% SIC PARTICLES THE JOINING PERFORmances of the similar conposites were studied and the influences of testing time and temperature on bonding quality and properties of the bonded joints were also estimated<\div>

۷Study of the performance of Oxide– based flux on the TIG welding of AISI 4140 steel
نویسنده(ها): ،
اطلاعات انتشار: اولین همایش ملی تکنیک های نوین در تجهیزات و مواد آزمایشگاهی صنعت نفت ایران، سال
تعداد صفحات: ۹
TIG welding is considered as one of the most common welding method because of high quality weld metal. For this reason, to increase the joint penetration during one–pass welding, actived–flux tungsten inert gas (A–TIG) welding on the 42CrMo4 steel type steel was studied. This paper presents effect of welding current and thickness of activating flux layer on the weld bead geometry.Two kinds of oxides Cu2O and Cr2O3 were used to investigate effect of activating flux on the weld bead geometry,microstructure and hardness in AISI 4140 steel. The effect of activated flux on metallurgicalproperties of the welds was discussed using result of scaning electron images, and EDS graphs of the weld zone for welds with or without fluxes. Vickers hardness with 500g force was performed. Experimental results showed that maximum depth of weld was obtained by using Cr2O3 activated flux but this flux decreased the depth to width ratio. All welds had martensite microstructure.<\div>

۸Behaviour of centrifugally cast 208.0 aluminum alloy at different pouring temperatures
نویسنده(ها): ،
اطلاعات انتشار: سومین کنفرانس بین‌المللی آلومینیوم ایران IIAC2014، سال
تعداد صفحات: ۵
This investigation studies effect of pouring temperature on microstructure and segregation of 208.0 aluminum alloy. The samples were cast at three different temperatures 850, 900 and 950°C. Characteristics and distribution of the primary particles were assessed by the optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and image analyzer software. The hardness along the thickness of samples was measured to investigate the variation in mechanical properties corresponding to the variation in microstructure. The results show that fine equiaxed grains and coarse columnar grains are formed at lower and higher pouring temperatures, respectively. Also as the pouring temperature increases, the rate of nucleation and solidification decreases due to slower heat transfer. In this situation, dendrites grow and dendrite–arm spacing increases. By raising pouring temperature from 850°C to 950°C, amounts of copper at external wall increases. Because the density of copper is higher (8.9 vs. 2.7 g\cm3), therefore copper moves towards the mould external wall due to a higher centrifugal force and intensify segregation<\div>
نمایش نتایج ۱ تا ۸ از میان ۸ نتیجه