composite base metal welded joints, the hardness distribu- tions through the cross-section of the weld metal of different ﬁller metals are shown in Fig. 14. Comparing to the hardness of the base metal (64 HV), the average hardness values inside the weld metal from all ﬁller metals were remarkably improved. Similarly to that of the AA 6028 base metal, the ﬁne eutectic structure formed from the high Si content of the Al-12%Si ﬁller metal increase the hardness of the weld metal to about 115 HV. The Al-Ti5-B1 master alloy-added ﬁller metals showed higher hardness in the weld metal. It reaches to about 117 HV for the 3 mass % added Al-Ti5-B1 master alloy. This can be due to the formation of ﬁ ne equiaxed grains in the weld zone and the reinforcing effect of the TiB 2
The process is single step and very ﬂexible as it can pro- duce nanoparticles or nanoporous materials of diﬀerent compositions such as nanoscale metals and metal oxides which can be used in energy generation applications. Also, this new technique can lead to promising solutions for development of better biomaterials and biocomposites for custom-designed, functionally graded bone implants and skeletal repair and also for the nanostructured surfaces for cell culture and tissue growth.
Abstract: Welding, as one of the most effective joining methods for metals, has been extensively applied in engineering usage since a long time. The determination of microstructure and mechanical properties of welded structures is thus of paramount importance to implement a damage tolerant approach to structural life extension. In this study, structural and mechanical properties evaluation of 31000-H2 (IS-737) Aluminium Alloy after single pass Tungsten Inert Gas (TIG) welding were investigated to reveal the yield strength, ultimate strength, percentage elongation, impact strength and hardness of welded joints. The TIG Welding results of aluminium alloys 31000-H2 for 5 mm plate thickness using different filler materials during welding are presented in this paper. Effect of welding was studied on four different zones like base Metal, weld metal heat affected zone and combined zone of base Metal and heat affected zone.
Table 2 shows the macro elements identified in this study. Macro-metals are the natural elements which the body needs more often and are more important than any other minerals. Among the macro-minerals measured Na (98.675 to 129.561 ppm from shop SPL1), (40.561 to 65.291 ppm, from shop FVL2) and (124 to 165.768 ppm, from shop SRL3), P (194.671 to 215.213 ppm, from shop SPL1), (98.452 to 115.061 ppm, from shop FVL2) and (198.578 to 289.901 ppm, from shop SRL3), Mg (19.815 to 39.067 ppm, from shop SPL1), (12.679 to 25.532 ppm, from shop FVL2) and (30.567 to 52.679 ppm, from shop SRL3) and Ca (2.091 to 8.765 ppm, from shop SPL1), (3.547 to 9.746 ppm, from shop FVL2) and (4.856 to 9.976 ppm, from shop SRL3) were obtained in large quantity. The obtained Na, Mg and Ca serve as principal cations while P serve as principal anion in the human body. Macro-minerals such as Na is a good electrolyte and the body uses electrolytes to maintain acid-base balance and fluid balance (homeostasis) for normal neurological, myocardial, nerve, and muscle function. Electrolyte activity usually
b) In case 2pressure amount of 279.75kpa is applied along the circumference of the wheel with the same materials as in case 1. The radial loads and fixed part are also kept same as case 1.Following are the conclusions from the results obtained:
The results obtained in our study showed 485.24 mg Cr kg -1 d.m. in soil. According to Bruenetti et al. (2009), Cr concentrations in the investigated soil samples ranged 36.18-115.15 mgkg -1 . The chromium is the contaminant with highest total contents in soils, but it showed only average extractability of 0.008%, and some authors (Z a y e d & T e r r y , 2003) have found that nearly all the soil Cr was in a more resistant fraction (less soluble forms). Not all metals provide the same bioavailability and metal bioavailability depend on the mineralogy of the soil. For example, the high-Cr concentrations in the serpentine soils often are in the form of chromite, an unalterable mineral, and so Cr remains not bioavailable. This is just one factor that affects the uptake of Cr. Regular Cr content in plants usually ranges 0.006-18 mgkg -1 (Ž i v k o v i ć
The quick development of innovation in ongoing decades has prompted the decrease of expense and weight of materials. The adjusted framework has turned out to be prevalent in industry and in research. Thus, there is decrease in mishap and wellbeing has expanded. Numerous enterprises use knuckle joint which is mix of two materials: cast iron and treated steel. Here we are changing the materials with better mechanical properties as required. The materials we are investigating are copper combination, magnesium compound and auxiliary steel. The proposed framework has numerous focal points over other framework, for example, making the gadget, less difficult and having most extreme security. The investigation of the framework demonstrates all highlights notice the abovementioned. The explanation behind considering composite materials (alloys) are properties, which will fulfil while in there working. Composite materials are portrayed by a high adaptability material. The progressive development in advancements in a year ago permitted diminishing anxiety.
Hydrogen based energy systems seem to be a very good approach for the future as the expansion of the clean energy storage and production technicues. At this point that is challenging issues of ongoing scientific studies. Presently, there is need for making better platinum based cathode catalysts for the oxygen reduction reaction. It could help to the platinum loading reduction . One of the methods to achieve high-effective electro catalysts is combining two or more metals togheter. Such procedure may lead to new surface phenomena, which can be interesting for their catalytic properties. For example, using Pt-alloys with the 3d and 4d-transition metals (e.g. Ni, Co, Ti, V, Zr, Fe) results in electro catalytic research [2-4] called ‘volcano-type.’ It seems, that for the Pt 3 M alloys the maximum in the catalytic activity is casued by the interaction
Abstract: Braking is the process which converts kinetic energy of vehicle into mechanical energy which must be dissipated in the form of heat. The brake is a mechanical device which inhibits the rotational motion of the wheel by the action of friction generated between shoe brake and the brake drum. During braking, the brake shoe experiences high temperature and thermal stresses. Due to this the brake shoe material should possess a high thermal conductivity, thermal capacity and high strength in order to withstand these stresses. The aim of this research is to design the brake shoe by using the finite element analysis. The most efficient material for the manufacturing of brake drum is found by analyzing different selected materials under given boundary conditions. This research emphasizing on the substitution of cast iron by any other lightweight materials. A model is created with the help of software CATIA V5 and structural and thermal analysis is performed in ANSYS 16.0 work bench. A static structural and thermal analysis of different materials such as aluminium alloy, aluminium metal matrix composite (1), aluminium metal matrix composite (2) and titanium alloy for a brake shoe lining is done. The results of all these four analysis are compared at the end to find out the most suitable material for brake shoe lining.
properties of these materials must be tested in a labo- ratory environment before clinical studies are initi- ated. Shear bond strength is a variable that has been tested extensively in metal-ceramic systems. The pre- sent findings are valid for the particular alloy and tech- niques used. The combination of indirect resin com- posites and their respective bonding systems, as recommended by the manufacturers, was chosen to avoid chemical incompatibilities. Another point that needs consideration is the variability in metal-resin bond strength values that may occur in a commercial laboratory setting because of technique sensitivity. The minimum bond strength that will suffice for clin- ical longevity has not been established. Comparisons of different systems are helpful in that perspective. These materials and techniques should be tested in vivo in long-term studies for more valid information.
Only a small number of metals, such as gold, silver and platinum are found in rock as uncombined metals. These are the most unreactive metals. These metals were among the first elements to be discovered because they did not have to be extracted from their ores in some way.
Studying and understanding the interaction between atoms on solid surfaces is one of the basic scientific problems in the field of surface physics. Therefore, con- trolling such self-assembling structures is important for the development of nanodevices. Atoms adsorbed onto a solid surface can interact indirectly through electron scattering or elastic distortion of the substrate, with the long-range atomic interaction modulated by the sub- strate playing an important role in atomic self-assembly. Because alkali-metal atoms can easily lose electrons, the adsorption of alkali metals onto semiconductor materials can change them to n-type, which will in turn reduce their work function and change their optoelectronic properties . In recent years, many research groups have reported studies of the optoelectronic properties of alkali-metal-adsorbed 2D materials [13–23]. For instance, Chan et al.  investigated the adsorption of alkali-metal atoms on graphene and discovered the reduction of work function of graphene. Jin et al.  and Qiao et al.  investigated the adsorption of alkali metals on graphene using first-principles method and
AD12.1 alloy and JIS.AC4C aluminum alloy (referred to hereinafter as AC4C alloy) were used for the type A experimental die casting. The compositions of AD12.1 alloy and AC4C alloy are Al11 mass%Si2.34 mass%Cu 1.2 mass%Mg and Al7 mass%Si0.3 mass%Mg, respec- tively, and the liquidus temperatures are 837 and 883 K, respectively. Molten metal was poured into a sleeve that was thermally insulated by Kaowool sheet (a sheet of ceramic ﬁbers made by Isolite Insulating Products Co., Ltd.) linings and was ﬁrst injected into the cavity by two-step injection at a low velocity of 0.03 m·s ¹1 followed by a high velocity of 0.7 m·s ¹1 . The injection was shifted from the low-velocity step to the high-velocity step when the tip of the ﬂowing molten metal reached a point 180 mm from the top surface of the biscuit. Die casting experiments were performed under casting pressures ranged from 30 to 65 MPa and injection temperatures of the molten metal ranging from 883 to 999 K. The injection temperature of the molten metal was estimated based on the initial temperature, the cooling curve in the sleeve of the molten metal and the injection time. The temperature of the molten metal during mold ﬁlling was measured using a thermocouple installed in the cavity at a point of 80 mm from the top surface of the biscuit. Surface fold defects 11) were observed in some of the die castings, as shown in Fig. 2(a). The surface fold defects were quantita- tively assessed according to the area of the dented surface of the die casting, which was measured from the binary image of the surface, as shown in Fig. 2(b). The micro- and the macro-structures of the low-velocity and the high-velocity ﬁlled portions were examined by cutting the die casting at positions a and b shown in Fig. 1(A).
From constructing buildings to manufacturing ships welding is the structural backbone to numerous industrial, commercial, and service sectors. Welding has numerous variables and various techniques; primarily driven by the base metal, weld rod, electrode, and environmental factors. Welding processes generate weld fume consisting of fine particles and heavy metals which contaminates the workspace environment creating a hazardous working environment for workers. Also, weld fume leaving the work environment further pollutes the surrounding air quality which results in public health concern. Weld fumes are vaporized when the electrode and base metal come in contact during welding operations. As the vaporized particles cool
Figure 2 shows the five product forms in the DMW in the ‘A’ hot leg nozzle to primary coolant pipe weld in the V.C. Summer Nuclear Station reactor coolant system (RCS). The nozzle is made of alloy 508, has a typical wall thickness of 5 cm, and is clad with 308 or 309 stainless steel that is typically 6 mm thick. The nozzle is buttered with alloy 182 to a thickness of approximately 1.5 cm on the weld preparation surface. Alloy 182 is used for the weld metal that joins the alloy 304 stainless steel pipe to the buttering. These product forms can vary; for example, the cold legs used at the V.C. Summer Nuclear Station have statically cast stainless steel elbows instead of alloy 304 safe-ends.
ference in the rate of inactivation between atoms and ions. The difference is expected to get wider when a lower concentration of metals is used as is normally the case with potable water disinfection with metals. On the other hand, it is noticed from Figure 9 shows that the time required for complete inactivation of E. coli falls much faster at low free energy of formation. Therefore, al- though cobalt and copper have a significant difference in energy of formation, the time required for inactivation does not vary much. The opposite is true for copper and silver. Both of these have low free energy of formation with a small difference in values (Table 1). However, the time required for inactivation with silver is much smaller than that of copper. This is a result of the increase in the number of protons in the silver ions compared to copper while the increased number of electrons is filled in the d- orbitals with poor shielding of the protons’ attraction po- tential.
mother alloy in the nozzle was melted with RF melting. Once a predetermined temperature was reached, molten metal was jetted from the nozzle oriﬁce promptly onto the copper roll surface rotating at high speed. Then the rapidly solidiﬁed ribbon was fabricated continuously. Spacing between the nozzle oriﬁce and the roll surface (nozzle gap) was set to 0.3 mm in this experiment. The copper roll was rotated at a speed of 23–39 m/s; the mother alloys were molten in the nozzle with RF melting at a temperature of 1473–1773 K. The surface temperature of molten metals on the roll was measured using a radiation thermometer (IR-CAQ; Chino Corp.) installed at the upper part of the apparatus. The surface temperature of the roll standing in the air was measured as around 285 K (room temperature: about 13 C) using a non-
This study investigates the correlation between the microstructure and the corrosion resistance properties of the fusion zone of Alloy 690- SUS 304L stainless steel dissimilar weldments formed by electron beam welding (EBW). The eﬀects of the EBW process are evaluated by comparing the microstructure and corrosion resistance properties of the EBW weldment with those of Alloy 690-SUS 304L weldment formed by gas tungsten arc welding (GTAW). The experimental results reveal that the interdendritic region of the fusion zone of the EBW weldment contains ﬁne TiN precipitates and Cr-Ni rich phases. The TiN precipitates are originated from the Alloy 690 base metal, while the Cr-Ni rich phases, a new formation of precipitates, is precipitated in the region around TiN during solidiﬁcation. Microscopic analysis of the samples following a modiﬁed Huey test indicates that the matrix around TiN precipitate and the Cr-Ni rich phase precipitate provide the preferred sites for corrosion pit initiation. Due to the rapid cooling in the EBW process, relatively fewer and smaller TiN precipitates and Cr-Ni rich phases are formed in the weldment. Consequently, only limited corrosive pitting is observed which indicates better interdendritic corrosion resistance properties in comparison to joints with GTAW process. Furthermore, rapid solidiﬁcation in the fusion zone results not only the suppression of chromium carbide precipitation but also the chromium depletion at the grain boundaries. As a result, the intergranular corrosion resistance and interdendritic corrosion resistance of the EBW weldment are signiﬁcantly higher than that of the GTAW weldment.
Zahid Amjad received his BSc in Chemistry (Honors) and MSc in Chemistry from the University of the Panjab, Pakistan, and PhD from Glasgow University, Scotland, United Kingdom. He was a lecturer at the Institute of Chemistry of Panjab University and served as an assistant research professor at the State University of New York at Buffalo, New York. He started his professional career as an R & D scientist. During his more than 30 years at Calgon Corporation, Pittsburgh, Pennsylvania, and Lubrizol Advanced Materials, Inc., Cleveland, Ohio, he has worked in various fields, including water treatment, water purification, cosmetics, home care, oral care, and pharmaceutics, and related fields.