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Advancement in Liquid Processing Techniques of Aerospace-Grade 7XXX Series Aluminium Alloy and Composites
Published in Suneev Anil Bansal, Virat Khanna, Pallav Gupta, Metal Matrix Composites, 2023
Vasanthakumar Pandian, Sekar Kannan
The squeeze casting generates high pressure to produce near net-shaped components to avoid porosity in the fabrication of MMC. Squeeze casting has its advantage when poured molten metal is forced with high pressure to decrease the adverse effects of porosity and reduces the gas entrapment and solidification shrinkage. Table 10.2 shows matrix alloy, reinforcement, and squeeze pressure of 7XXX series aluminium alloy and composites. Kannan and Ramanujam (2018) reported that AA7075 cast with Al2O3, h-BN reinforcement with maximum squeeze pressure of 150 MPa. George and Knutsen (2012) used a 130-ton pressure for AA7075 without reinforcement. Blaz et al. (2010) suggested that the pressure of 100 Mpa can be used to cast AA7039-SiC composite. Kannan and Ramanujam (2017) used the same pressure as Blaz et al. (2010) suggested for AA7075-Al2O3 composite.
Sources of Stress and Service Failure Mechanisms
Published in Colin R. Gagg, Forensic Engineering, 2020
Major production systems are based on metal mould processes, such as die, or permanent mould casting, which use either pressure or gravity feed in the casting process. Another metal mould process is centrifugal casting, which takes advantage of radial forces on the solidifying product to reduce casting porosity; it is, for example, used to produce pipes. More recently, technologies that encompass squeeze casting have taken advantage of mechanical forces on the solidifying metal. The semi-solid metal casting (SSM) process routes of thixo-casting, rheo-casting, thixo-forming or thixo-molding are near net shape processes utilised for the production of non-ferrous metal parts, where the process combines the advantages of both casting and forging. The process is named after the fluid property thixotropy, which is the phenomenon that allows this process to work. Simply, thixotropic fluids shear when the material flows, but thicken when standing.
Magnesium and Its Alloys
Published in Omar Faruk , Jimi Tjong , Mohini Sain, Lightweight and Sustainable Materials for Automotive Applications, 2017
D. Sameer Kumar, C. Tara Sasanka
Squeeze casting is a combination of the forging process and casting process. In direct squeeze casting, shown in Figure 10.6, molten metal is poured slowly with a minimal amount of turbulence into the lower half of a die. An upper punch is pressed down on the metal, once the die cavity is filled. The metal solidifies under this high, unidirectional pressure which in turn reduces any internal defects during solidification. Direct squeeze casting, however, allows for the trapping of impurities within the metal as it does not have a runner system. Incidentally, this also results in high internal integrity material. Indirect squeeze casting involves molten metal being poured into an encasement. A plunger is then used to control the speed at which the metal flows into the mold to eliminate the gas bubbles within the casting. There is a lower material yield with indirect squeeze casting due to greater material loss [23].
Parameter Optimisation of Squeeze Casting Process using LM 20 Alloy: Numeral Analysis by Neural Network and Modified Coefficient-based Deer Hunting Optimization
Published in Australian Journal of Mechanical Engineering, 2023
Pratheesh G Panicker, Shajan Kuriakose
Casting is one of the difficult manufacturing processes with a huge set of procedures and variables. Squeeze casting combines the effect of mould forging and casting. The basic principle of squeeze casting is pressurised solidification. Comparing with several conventional casting procedures, the squeeze has got many benefits such as the least amount of porosity, treatable heat, weldable, elevated productivity; better properties of mechanical products, improved surface finish, excellent cast ability, and advanced microstructure of non-ferrous and ferrous particular alloys (Ghomashchi and Vikhrov 2000). The squeeze casting process has capabilities like comparatively elevated filling pressure and low filling speed, as a result, it improves the ability of feeding (Ghomashchi and Vikhrov 2000). Meanwhile, it helps for a wide range of applications in the view of highly developed forming technology, which can enhance the coefficient of heat transfer and the alloy cooling ability that cast to acquire a slighter casting microstructure (Ghassemali, Jarfors, and Dioszegi 2018) (ManjunathPatel, Krishna, and Parappagoudar 2014). It is paramount to note that the squeeze casting product quality is mainly influenced by process parameters namely squeeze pressure, pressure duration, pouring temperature, and Die preheat temperature. Generally squeeze casting fabricated engineering components are fine-grained with excellent surface finish and have almost no porosity (Ghomashchi and Vikhrov 2000).
Experimental and numerical evaluation of squeeze cast Al-Si-Cu-Ni-Mg alloy for piston applications
Published in Materials and Manufacturing Processes, 2022
Hari Sanil, T.K Deepak, M. Ravi
Gravity die casting and forging are the most common techniques used for manufacturing engine pistons. The drawbacks with the die casting method is the formation of defects such as gas porosity, hot tear cold crack, shrinkage porosity.[22] The forged components are used to observe with a non-uniform microstructure.[23] In order to overcome the above drawbacks, number of efficient casting techniques have been developed.[24] In particular, squeeze casting allows the production of castings with lower defects and with enhanced mechanical properties. It integrates the both forging and casting characteristics into a single operation.[25] A review by Sarfraz et al.[26] gives a clear indication that squeeze casting is a fast-growing method for broad use in Al manufacturing industries. The major attractions of the process are the metallurgical advantages compared to other manufacturing techniques and the potential cost reduction compared with forging.[27–30] However, the quality of the squeeze cast component depends on the squeeze pressure as well as the molten metal pouring temperature. Sukumaran et al.[28] studied the effect of pressure on eliminating the casting defects. They obtained better mechanical properties and refined microstructure with negligible porosity when using the optimum pressure. Jahangiri et al.[29] also highlighted that the optimum pouring temperature and squeeze pressure are required to obtaining sound castings. Despite the industrial interest in the squeeze casting technique, there is only a limited scientific understanding of how solidification pressure affects the thermal conductivity.
Comprehensive studies on processing and characterization of hybrid magnesium composites
Published in Materials and Manufacturing Processes, 2018
The pressure applied during stir casting is critical, as it affects the metallurgical and mechanical behaviour of the cast products.[47,105,106] The high pressure can cause many alterations in the melt during solidification. Such alterations include (i) changing the freezing temperature; (ii) increasing the cooling rate as the mould walls and melt come nearer to one another, causing a greater amount of heat transfer; (iii) reducing the shrinkage-producing fine grain structure with high density, strength, and ductility; and (iv) removing runner and riser use. Hence, the benefits of squeeze casting over stir casting include low porosity, low shrinkage, and fine grain structure, thereby providing superior mechanical properties and the ability to involve a greater volume (<50%) of reinforcements.[8990919293949596979899100101102103104105106107108] Still, very high pressure cannot be used during squeeze casting, as excessive pressure may result in (i) the oxidation of Mg and gas entrapment caused by the turbulent flow of liquid Mg and (ii) damage to the reinforcing phases, thereby deteriorating the mechanical properties of the cast products. Taking care to control the application of pressure is essential in squeeze casting. There are shape and dimension constraints to consider when employing squeeze casting possesses, and, therefore, squeeze casting is not preferred for mass production.[65] Recent advancements in squeeze casting for processing Mg composites involves a two-step process (i.e., low-pressure infiltration and high-pressure solidification) to surpass the adverse effects of high-pressure casting.[100,109,110]