Semi-solid Squeeze Casting Research Articles

Effect of solid solution treatment on microstructure and mechanical properties of Al–Si–Cu–Mg alloy prepared by semi-solid squeeze casting

Effect of solid solution treatment on microstructure and mechanical properties of Al–Si–Cu–Mg alloy prepared by semi-solid squeeze casting

Effect of Ingate Length on Microstructure and Properties of Semi-Solid Squeeze Casting CuSn10P1 Alloy

It is easy to occur solid-liquid separation during semi-solid rheological forming, which leads to poor uniformity of microstructure and properties and limits its application in high strength and toughness parts. In this paper, a semi-solid CuSn10P1 alloy slurry was prepared by an enclosed cooling slope channel (for short ECSC). The effect of ingate length on microstructure and properties by semi-solid squeeze casting was studied. The results showed that the proper increase of the length of the ingate is beneficial to improve the uniformity of the microstructure and properties of the semi-solid squeeze casting. The microstructure uniformity and properties are the best when the ingate length is 20mm. The ultimate tensile strength and elongation of semi-solid squeeze casting CuSn10P1 alloy with 20 mm ingate length reached 419.2 MPa and 13.4%.

Effect of Runner Distance on Microstructure and Properties of Semi-Solid Squeeze Casting CuSn10P1 Alloy

It is easy to form reverse segregation and shrinkage porosity defects during the solidification of CuSn10P1 alloy, which leads to the poor properties and limits its application in high strength and toughness parts. In this paper, semi-solid CuSn10P1 alloy slurry was prepared by enclosed cooling slope channel (for short ECSC). The effect of runner distance on microstructure and properties by liquid squeeze casting and semi-solid squeeze casting was studied. The results showed that the microstructure of semi-solid squeeze casting is finer than that of liquid squeeze casting, and the shrinkage defects are improved. The solid fraction with 65 mm runner is lower than that without runner in liquid squeeze casting and semi-solid squeeze casting due to the retention effect of solid phase in semi-solid slurry flow, but the properties with 65 mm runner is better than that without runner. The ultimate tensile strength, yield strength and elongation of semi-solid squeeze casting CuSn10P1 alloy with 65 mm runner distance reached 466.5 MPa, 273.6 MPa and 13.4%, which were improved by 26%, 19% and 97%, respectively, as compared to that of liquid squeeze casting.

Effect of solution time on microstructure and mechanical properties of Al-17Si-4Cu-0.5Mg alloy formed by semisolid squeeze casting

Effect of solution time on microstructure and mechanical properties of Al-17Si-4Cu-0.5Mg alloy formed by semisolid squeeze casting

Comparison of the semisolid squeeze casting and gravity casting process on the precipitation behavior and mechanical properties of the Al-Si-Cu-Mg alloy

The differences in microstructure, ageing behavior and mechanical properties of the Al-17.8Si-4.3Cu-0.4Mg alloy formed by semisolid squeeze casting and gravity casting processes were investigated. It was found that a nearly equiaxed microstructure of α-Al, finer and denser Si phases, and a higher dislocation density exist in the semisolid extruded sample. In the peak ageing state, θ” and Q' phases are mainly observed under the two forming processes, while the precipitate increases and the size decreases after semisolid extrusion. According to the thermodynamics, the binding energy and enthalpy values of Q′ phase are lower than those of the θ' and θ″ phases. Therefore, among the three metastable phases, the Q′ phase precipitated before the θ″ and θ' phases. The semisolid extruded alloy exhibits higher strength and ductility in the as-cast state and T6 state. This might be caused due to more uniform microstructure and finer precipitating phase. Double ageing hardness peaks were found in the age-hardening curves of Al-17.8Si-4.3Cu-0.4Mg alloys under both processes, which were related to the influence of the precipitation sequence of the alloy. • Microstructure and properties of Al-Si -Cu-Mg alloy by semisolid extrusion and gravity casting was studied. • Better comprehensive mechanical properties were obtained after semisolid squeeze casting process. • There were two hardness peaks corresponding to the ageing time of 6 and 12 h under two forming processes. • Compared to gravity casting, the size of the precipitates in the semisolid extruded samples was smaller.

The effect of squeeze casting process on the microstructure, mechanical properties and wear properties of hypereutectic Al–Si–Cu–Mg alloy

The effects of the squeeze casting process on the microstructure, mechanical properties and wear characteristics of hypereutectic Al–Si–Cu–Mg alloys have been investigated by optical, scanning and transmission electron microscopy and mechanical property test; the wear behaviour was investigated using a pin-on-disc configuration; alloy ingots were prepared by gravity casting, liquid squeeze casting and semisolid squeeze casting. The results show that the Si phase was refined and the α-Al dendrites transformed to rosette grains after semisolid squeeze casting. The peak intensity of the second phase decreased after extrusion, indicating that extrusion promotes the dissolution of solute elements into the matrix. Among the three casting processes, the alloys formed by semisolid squeeze casting had the best mechanical properties. Tensile strength, elongation and Brinell hardness reached 187.67 MPa, 2.33% and 142.5 HB, respectively. After semisolid squeeze casting, the morphology of the wear surface was flat and the number of spalling pits and furrows is less. Meanwhile, the friction coefficient and wear loss of the alloy sample are minima. Due to the uniform distribution of Si phases and equiaxed crystallization of α-Al phase in semisolid squeeze casting Al–Si–Cu–Mg alloys, the wear resistance is markedly enhanced.

Adjusting the Si Phase and Forming Nanoprecipitation to Improve the Mechanical Properties of Al–Si–Cu–Mg Alloy by Heat Treatment

To adjust the morphology of the Si phase and improve the mechanical properties of Al–Si–Cu–Mg alloy formed by semisolid squeeze casting, the effects of solution time on microstructure evolution and mechanical properties are systematically studied. Results show that spheroidization occurs in the Si phase, and the content of Cu in the matrix increases simultaneously after solution treatment at 525 °C for 1 h. As solution time increases to 8 h, the content of Cu in the matrix increases from 1.15% to 1.41% and the dislocation density decreases. After an aging treatment at 180 °C for 12 h, the β′, θ′, and Q′ phases precipitate. After heat treatment, the alloy strength value shows a “double peak” phenomenon. After a 1 h solution treatment, the tensile strength of the alloy reaches the first peak, which is mainly ascribed to the large dislocation density induced by the semisolid squeeze casting process. When the solution time is 8 h, the tensile strength of the alloy is 323 MPa and the tensile strength reaches the second peak, which is ascribed to the rounding of the Si phase and the strengthening effects of fine precipitates.

Effects of process parameters on semi-solid squeeze casting performance of aluminum alloy scrolls for scroll compressors

The aluminum alloy scroll is one of the key parts of the scroll compressors widely used in the air-conditioning, refrigeration, and heat pump systems. In this work, the semi-solid squeeze casting (SSSC) process was used to fabricate the aluminum alloy scroll. The effects of process parameters including the pouring temperature, mold temperature, and squeezing velocity on the filling and solidification behaviors of the alloys were investigated through simulations based on the power law cut-off (PLCO) material model. Results show that there is a significant increase in the flow velocity of the slurry, and the area of the high-speed region enlarges with the increase of the pouring temperature. The homogeneity of the temperature and velocity fields in the slurry is improved with an increase in mold temperature. Both the filling time and its variation rate decrease with an increase in squeezing velocity. The maximum solidification time exhibits a linear variation with the increase in pouring temperature. The shrinkage area is decreased by increasing the mold temperature. The optimal process parameters of the SSSC process were obtained from simulation analysis, which are the pouring temperature of 595 °C, mold temperature of 350 °C, and squeezing velocity of 0.3 m·s−1. Moreover, the qualified scroll casting was fabricated using the SSSC process under the optimal process parameters.

Influence of semisolid squeeze casting technology on alpha phase and eutectic of AlSi7Mg0.3

The paper deals with processing of material in semisolid state by the technology of semisolid squeeze casting. The investigated material was a subeutectic aluminium alloy AlSi7Mg0.3. The influence of various preparation meth-ods of batch material on the structure after processing by this technology was studied. Alloy AlSi7Mg0.3 was pre-pared as gravity cast, inoculated, heat treated and by technology of direct squeeze casting. In article is assessed microstructure of castings before and after processing by technology of semisolid squeeze casting. The shape and distribution of eutectic silicon was observed. The shape and the distribution of alpha phase formations has an im-pact on whether micro-volumes of molten eutectic will be closed in alpha phase or will be segregated along the boundaries of alpha phase formations. It was observed the partial inheritance in microstructure. Also the segrega-tion in surface layer was observed.

Effect of heat treatment on microstructure and properties of semi-solid squeeze casting AZ91D

Semi-solid AZ91D magnesium alloy billets were prepared by near-liquidus heat holding. Semi-solid squeeze casting was conducted at 575, 585 and 595 °C, respectively, with 1 mm·s−1 squeeze speed. The semisolid squeeze casting AZ91D samples were heat treated by T4 (solution at 415 °C for 24 h) and T6 (solution at 415 °C for 24 h + 220 °C for 8 h) processes, respectively. The microstructure and mechanical properties of the alloy in different states were investigated by means of OM, SEM and tensile testing machine. The results show that compared to as-cast alloy, the grain size of the semi-solid squeezed AZ91D decreased significantly, and with the increase of semi-solid squeeze temperature, the grain size of AZ91D increased. The grains of the alloy were refined by T4 treatment, and further refined by T6 treatment. T6 treatment greatly improved the tensile strength, elongation, and hardness, but did not significantly improve yield strength. After 575 °C squeeze casting and T6 treatment, the ultimate tensile strength (UTS) reached 285 MPa, the elongation reached 13.36%, and the hardness also reached the maximum (106.8 HV), but the yield strength (YS) was only 180 MPa. During the process of semi-solid squeeze casting and heat treatment, the matrix grain was refined and a large number of precipitated and secondary precipitated phases of Mg17Al12 appeared. Both the average size of matrix grain and secondary precipitated phase decreased, while the volume fraction of secondary precipitated phase increased. All these resulted in high tensile strength, elongation and hardness.

Simulation Fluidity Test for Semisolid Squeeze Casting

The paper deals with semi solid squeeze casting technology. Fluidity tests were designed for the selected technology. The shape of the test casting was designed in the shape of test bars with different thicknesses and also in the shape of a stepped casting. The thickness of the individual elements was chosen on the basis of a selected / preferred numbers R10 EN STN 17. As a result, the thickness of the elements was 2.0, 2.5, 3.15, 4.0, 5.0 and 6.3 mm. Designed fluidity tests were verified by using ProCast simulation software. The selected process parameters were: operating pressure 80 MPa, mold temperature 200 °C, piston speed 30 mm.s-1. The experimental material was an AlSi7Mg0.3 alloy with a different solid phase content. The initial solid amount were 50, 55 and 60 %. The effect of solidus and liquidus, temperature distribution and pressure was monitored during the evaluation of fluidity.

Evolution of Microstructure and Mechanical Properties of Semi-Solid Squeeze Cast A356.2 Aluminum Alloy during Heat Treatment

Semi-solid squeeze casting (SS-SC) is a new processing technology which combines semi-solid processing (SSP) and squeeze casting (SC). In this process, semi-solid slurry fills mold by using its rheological property and solidifies under high pressure. It has several advantages, such as stable filling, small heat impact to the mold, low cost, high density and excellent mechanical properties of castings, which receives more and more attention. The microstructure of castings provided by SS-SC is quite different from that of casting provided by conventional SC in as-cast condition, which leads to differences in the evolution of microstructure and mechanical properties in heat treatment process. In this study, A356.2 aluminum alloys castings were provided by both SS-SC and conventional SC respectively. The evolution of microstructure and mechanical properties of castings during heat treatment was investigated to obtain the best mechanical properties of semi-solid squeeze castings. Keywords:Microstructure, Mechanical properties, Heat treatment, A356 alloy, Semi-Solid Squeeze Casting

Microstructure and mechanical properties of Mg97Zn1Y2 alloy reinforced with LPSO structure produced by semisolid squeeze casting

Effects of semisolid squeeze casting (SSC) process on microstructures and mechanical properties of the LPSO structure reinforced Mg97Zn1Y2 alloy were studied by optical microscopy, SEM equipped with EDS, TEM, XRD and Nanoscale indentation for the first time. The LPSO structure and α-Mg grains in the Mg97Zn1Y2 alloy can be refined significantly by SSC. The gran size of α-Mg was decreased from 170 µm to 109 µm, and the LPSO structure could be distributed uniformly in the alloy under the combined action of ultrasonic vibration (UV, preparation for semisolid slurry) and squeeze casting (SC). The type of LPSO structure was remained as the initial 18R-type structure after SSC, but a strip YZn3 phase precipitated out inner the block LPSO structure, which has never been found in the LPSO-containing Mg97Zn1Y2 alloy. With the increase of squeeze pressure, the amount of YZn3 phase was increased and the tensile strength and elongation of the alloy were increased at first and then maintained nearly constant. When the pressure was 100 MPa, the optimum mechanical properties were obtained. The yield strength, ultimate tensile strength and elongation were 141 MPa, 234 MPa and 11.6%, which were enhanced by 28.2%, 11.1% and 45.1%, respectively, compared with those of the alloy without SSC.

Microstructure and Properties of Semi-solid ZCuSn10P1 Alloy Processed with an Enclosed Cooling Slope Channel

Semi-solid ZCuSn10P1 alloy slurry was fabricated by a novel enclosed cooling slope channel (ECSC). The influence of pouring length of ECSC on the microstructures of ZCuSn10P1 alloy semi-solid slurry was studied with an optical microscope an optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). Liquid squeeze casting and semi-solid squeeze casting were performed under the same forming conditions, and the microstructure and properties were compared. The results show that primary α-Cu phase gradually evolved from dendrites to worm-like or equiaxed grains under the chilling action of the inner wall of the ECSC. The mass fraction of tin in the primary α-Cu phase increased from 5.85 to 6.46 after the ECSC process, and intergranular segregation was effectively suppressed. The finest microstructure can be obtained at 300 mm pouring length of ECSC; the equivalent diameter is 46.6 μm and its shape factor is 0.73. The average ultimate tensile strength and average elongation of semi-solid squeeze casting ZCuSn10P1 alloy reached 417 MPa and 12.6%, which were improved by 22% and 93%, respectively, as compared to that of liquid squeeze casting.

Microstructures and mechanical properties of semi-solid squeeze casting ZL104 connecting rod

Abstract Semi-solid squeeze casting (SSSC) and liquid squeeze casting (LSC) processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size (APS) and the shape factor (SF) increased with the increase of re-melting temperature (Tr), whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature (Tm), whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure (ps) increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.

Using Semi-Solid Extrusion for the Production of Aluminum-Nanocomposite Master Alloys

The production of nanoreinforced aluminum alloys in volume and quality suitable for subsequent shape casting has been problematic. Large specific surface area and high interfacial energy of the particles combined with high surface tension of the aluminum melt makes it difficult to add appreciable numbers of particles to the melt, even when later de-agglomerated by techniques such as ultrasonic cavitation. Previous work by the authors used semi-solid squeeze casting to produce master alloys for dilution into the casting alloy. While the technique was shown to be effective, the master alloy proved difficult to remelt and was expensive to produce. The objective of this new work was to use an extrusion process that could be more readily scaled to produce nanoreinforced aluminum master alloys. This paper describes the process developed for incorporation of nanoparticles using semi-solid extrusion and the results of alloys produced using that process.

Effect of process parameters on microstructure and mechanical properties in AlSi9Mg connecting-rod fabricated by semi-solid squeeze casting

The effects of applied pressure, pouring temperature and die temperature on the microstructure and mechanical properties of connecting-rods fabricated by the semi-solid squeeze casting (SSSC) process were investigated. The results show that the non-dendritic primary α-Al particles distribute uniformly throughout the connecting-rods. With the increase of applied squeeze pressure, the size of α-Al particles decreases while the shape factor increases, which increase the mechanical properties of the connecting-rods. When the pouring temperature and die temperature increase, the size and shape factor of primary α-Al particles increase. However, if the die temperature is higher than 300°C, the shape factor decreases suddenly. The best microstructure and mechanical properties of connecting-rods fabricated by SSSC were obtained at the pouring temperature of 575°C, die temperature of approximately 250°C, and squeeze pressure of 100MPa.

The structural evolutions of ZL109 alloy and 7050 alloy in the semisolid squeeze casting process

The structure evolutions of ZL109 alloy and 7050 alloy were studied in the processes of preparing raw billets by low super heat casting, remelting the raw billets, semisolid forming and heat treating components. The thin and symmetrical structure was obtained by using low super heat casting process. The eutectic that lied in the raw billet of ZL109 alloy remelted and produced liquid phase in the process of remelting, but to the 7050 alloy, the eutectic of intergranular and the pointedness of grains was remelted to make the grains more uniform and smooth. In the process of semisolid forming, the primary α and the eutectic inside the ZL109 alloy were separated partly and the grains in the 7050 alloy was conglutinated together. After heat treatment, the eutectic α grains of ZL109 traveled to primary α and shaped the white fishing net like organization; the eutectic Si grains assembled into the black massive particles. As to 7050, after heat treatment, α particles recrystallized and thin grains pattern was obtained.

Semi-solid squeeze casting process of a ZL109 alloy

The structure evolution of the ZL109 alloy in the process of semi-solid squeeze casting and the mechanical properties of the components were investigated. The results show that (1) the eutectic silicon phase in original billets is refined in the low super-heat casting process; (2) the eutectic structure in billets starts to fuse and the crystals of the eutectic silicon phase are refined further and sphericized in the remelting process of billets; (3) in the semi-solid squeeze casting process, the sphericity of the α phase and the refining of the silicon phase occur, owing to the friction between solid and liquid; (4) in the process of heat treatment, the eutectic α phase aggregates with the primary α phase and the eutectic silicon pieces aggregate together. The elongation of the semi-solid component after heat treatment rises to 1.42%.

Development of Non-Dendritic Microstructures in AA6061 Cast Billets

Non-dendritic structures have been shown to have many advantages over conventional, dendritic structures in castable aluminum alloys. Examples include high structural integrity, reduced porosity, excellent formability and enhanced near net-shape forming capability. Non-dendritic materials are characterized by an equiaxed, globularized grain structure. Previous work has focused on the application of these structures in traditional casting alloys such as A356 and A357, and on the processing of these alloys during semi-solid forming and squeeze casting. There is considerably less information on the impact of non-dendritic microstructures upon solid state deformation, and the use of such microstructures in the processing of traditional wrought aluminum alloys. In this paper, we will present our recent work in casting non-dendritic AA6061 alloy using different techniques, and discuss the effects of cast structure on deformation behavior during solid state processing at elevated temperatures. Cast microstructures were modified during direct chill casting using three different methods: magneto-hydrodynamic (MHD) agitation, mechanical stirring, and high loadings of grain refiner. A detailed microstructure characterization will be presented and discussed in terms of structural integrity, grain morphology, and their effects on deformation in the solid state.