Single crystal supealloy is a Ni-based alloy, and it consists of many elements，including Ni, W, Mo, Al, Ti, Re, etc. Usually, there is some composition segregation and low melting point eutectic formed in the surface of single crystal casting without tin, see Fig.1 (b). However, if the single crystal casting has a tin layer on the casting surface, tin will react with Ni in the interface between single crystal casting and tin layer. The reaction is closely related to the solidification process. When the model shell was immersed in the tin bath, the liquid superalloy was cooled by tin. Because of the contraction of solidified superalloy, gap will be formed between the model shell and solidified superalloy. The liquid tin will penetrate at some …show more content…
The oxide layer plus a reaction layer spalled partly because the stress induced by temperature change, and the other part of the reaction layer was remained after heat treatment, see Fig. 2(c). That is the reason why there is no oxygen in the EDS measurements in points “1”-“5” in Fig. 2(d). The quantity of the IMC layer thickness becomes difficult due to the spalling of the reaction layer. During the heat treatment procedure, Sn gradually diffuses into the surface of Ni based superalloy and the concentration of Sn in Ni superalloy increases. So (+')(Sn) eutectic volume fraction is increased after heat treatment, as shown in Fig. 2(c) and (d). The size and volume fraction of (+')(Sn) eutectic increase apparently because the Sn diffuse into superalloy and enlarge the eutectic solidification range. At the meantime, the recalescence behaviour lead the primary eutectic was halting and fine second eutectic formed, similar to the paper [24]. The reason why the recalescence behaviour took place is as follows: (i) The solidified lateral heat was dissipated into the front of eutectic during solidification and that lead the local temperature increase; (ii) the eutectic liquid was supercooled because it’s low melt point and no nucleate arising; (iii) the solidified rate of second …show more content…
The initial diffusion of Sn may be only taking place on the surface of single crystal superalloy. But as the time increasing Sn may diffuse into the superalloy substrate. Generally, the diffusion behaviour between Sn and Ni affects the microstructure evolution. The atomic mobilities of Sn and Ni in fcc Ni-Sn alloys were assessed as a function of temperature [26]. Besides, the solidified defects can accelerate the diffusion, such as grain boundary and micro porosity. For single crystal superalloy, the typical solidified defect is the micro porosity, which is mainly located in the interdendrite. The micro porosity is easy to observe in XRT micrograph. XRT micrograph of porosities in bulk sample seems in disorder, but in very thin casting the micro porosity is aligned along the interdendrite. Sn atom diffuses into the porosity located in interdendrite easily and enrichment near the porosity during heat treatment. With the diffusion of Sn, (+') (Sn) eutectic will be formed. As a result (+') (Sn) eutectics are near the porosities located in interdendrite region, as shown in Fig.5 (d). However, the distribution of (+') (Sn) eutectic is in disorder, see Fig. 3(c), this is the effect of the large size of bulk casting and observed sample position. During the formation of +' eutectic Sn atoms were rejected into the +' eutectic front end, due to the Sn
The endothermic melting temperature for Ptx, blank S-SEDDS, physical mixture of Ptx/blank S-SEDDS, and Ptx-loaded S-SEDDS was determined by DSC 2920. Samples were scanned from 30 to 250 °C at a rate of 10 °C /min. In all the cases, an empty pan was used as the reference. XRD patterns of Ptx, blank S-SEDDS, physical mixture of Ptx/blank S-SEDDS and Ptx-loaded S-SEDDS were recorded using an X'Pert PRO Multipurpose X-Ray diffractometer equipped with CuKα radiation (40 kV, 20 mA). The 2θ scanning range was varied from 2° to 50°.
Nitinol is a metal amalgam made up of nickel and titanium, these two components are available in equivalent nuclear rate. Nitinol amalgams show two firmly related and extraordinary properties: shape memory effect (SME) and superelasticity. Shape memory is the capacity of nitinol to experience misshapening at one temperature, then recuperate its unique, undeformed shape after warming over its "change temperature". Superelasticity happens at a restricted temperature extend simply over its change temperature; for this situation, no warming is important to bring about the undeformed shape to recuperate, and the material shows tremendous flexibility, some 10-30 times that of standard metal.
"Production of Refractory Metal Powders," in Powder Metal Technologies and Applications, vol. 7, 1998, pp. 188-201.
Aluminum is a lightweight, silvery metal. The atomic weight of aluminum is 26.9815; the element melts at 660° C (1220° F), boils at 2467° C (4473° F), and has a specific gravity of 2.7. Aluminum is a strongly electropositive metal and extremely reactive. In contact with air, aluminum rapidly becomes covered with a tough, transparent layer of aluminum oxide that resists further corrosive action. For this reason, materials made of aluminum do not tarnish or rust. The metal reduces many other metallic compounds to their base metals. For example, when thermite (a mixture of powdered iron oxide and aluminum) is heated, the aluminum rapidly removes the oxygen from the iron; the heat of the reaction is sufficient to melt the iron. This phenomenon is used in the thermite process for welding iron .
“Powder” is a story about an adolescent boy and his father on a ski trip, whose relationship is not always apparent between the two. The standard role of the father and son has been reversed in this story. The adult in the relationship is not always who it expects to be; in this situation, the boy is more like a man, and the father is more like the boy. There is a reflection of a modern day “broken” home situation between the parents, who seem to be on the verge of a divorce. They story is told from a first-person perspective of the boy. This way we see the boy’s thoughts and feelings about his emotional position. The father has promised the mother that he will have the son back on time for Christmas Eve dinner. Keeping this promise is important for the father because he seems to want to prove himself to the mother.
In order to separate the mixture of fluorene, o-toluic acid, and 1, 4-dibromobenzene, the previously learned techniques of extraction and crystallization are needed to perform the experiment. First, 10.0 mL of diethyl ether would be added to the mixture in a centrifuge tube (1) and shaken until the mixture completely dissolved (2). Diethyl ether is the best solvent for dissolving the mixture, because though it is a polar molecule, its ethyl groups make it a nonpolar solvent. The compounds, fluorene and 1, 4-dibromobenzene, are also nonpolar; therefore, it would be easier for it to be dissolved in this organic solvent.
Melting Point Determination of Alum 1. 0.5 g of dry alum was crushed with the mortar and pestle, and then the crushed alum was packed to the bottom the capillary tube. The alum measured about 0.5 cm from the bottom of the tube. Then the tube was fastened to the thermometer with the rubber band, and the thermometer was fastened to the ring stand with the universal clamp. 2.
The Synthesis of Alum from Aluminum lab centralized on the creation of potassium aluminum sulfate dodecahydrate from a set amount of aluminum, and using quantitative analysis to then compare the actual yield to the theoretical yield. The synthesis of alum was conducted through a series of steps involving aluminum foil, potassium hydroxide, and sulfuric acid. Given that aluminum is amphoteric, meaning it can dissolve in both strong acids and strong bases, potassium hydroxide and sulfuric acid were both suitable for the dissolution of aluminum. There are multiple applications to synthesizing alum; from eliminating waste in the environment by repurposing, to utilizing alum as a medical treatment, the practicality of alum is immense.
After quenching, the heated steel will cool down. Due to the different rate of cooling, the different types of microstructure will be formed. The formation of pearlite, bainite and martensite determine the physical properties such as hardness, strength and ductility.
Aluminum is one of a number of soft metals that scientists call "poor" metals. It can be shaped and twisted into any form. It can be rolled into thick plates for armored tanks or into thin foil for chewing gum wrappers. It may be drawn into a wire or made into cans. Aluminum is a generally popular metal because it does not rust and it resists wear from weather and chemicals. (Bowman, 391) Aluminum is an element. Its atomic number is thirteen and its atomic weight is usually twenty-seven. Pure aluminum melts at 660.2ºC and boils at 2500ºC. Its density is 2.7 grams per cube centimeter. Aluminum is never found uncombined in nature. (Bowman, 391) Aluminum is a very useful metal that is light, easy to shape and can be strong. This makes aluminum one of the most used metals in the world, right behind iron and steel. (Geary, 185) In its pure state, aluminum is quite weak compared to the other metals. However, its strength can be greatly increased by adding small amounts of alloying elements, heat-treating, or cold working. Only a small percentage of aluminum is used in its pure form. It is made into such items as electrical conductors, jewelry, and decorative trim for alliances and cars. A combination of the three techniques has produced aluminum alloys that, pound for pound, are stronger than structural steel. Some common metals used in alloys for aluminum are copper, magnesium and zinc.(Walker, 31) The added elements give the aluminum strength and other properties. (Newmark, 41) Aluminum is one of the lightest metals. It weighs about 168.5 pounds per cubic foot, about a third as much as steel which weighs 487 pounds per cubic foot. (Neely, 214) As a result, aluminum has replaced steel for many uses. For example, some ...
The manufacturing process of steel container or drum which is also known as liquid carrying container involves many processes. Although, there are different sizes of steel containers and different manufacturing process in most steel container manufacturing industries lately. There are also thousands of different steel alloy used in the production of steel containers. Furthermore, steel containers are made of sheet metal by soldering, brazing, spot welding, and seam welding. In addition to this, The Process of making steel containers involves rolling of metal sheet; welding the seam, making 90 degree bent on top and bottom of the container, making number of beads (according to size) and lastly reduce the diameter of one side of the container; fitting of lid to the containers, testing like pressure; coating internal (epoxy phenolic coating or plain) and external (stoving enamel gloss of various colour).
The Web. The Web. 28 Apr. 2014. The 'Standard' of the 'Standard'. Metal Melting 101 - How To.
Metals possess many unique fundamental properties that make them an ideal material for use in a diverse range of applications. Many common place things know today are made from metals; bridges, utensils, vehicles of all modes of transport, contain some form of metal or metallic compound. Properties such as high tensile strength, high fracture toughness, malleability and availability are just some of the many advantages associated with metals. Metals, accompanied by their many compounds and alloys, similar properties, high and low corrosion levels, and affects, whether negative or positive, are a grand force to be reckoned with.
In summary, the rate of cooling from the austenite phase is the main determinant of final structure and properties.