The implementation of high pressure die casting （HPDC） filling process modeling based on smoothed particle hydrodynamics （SPH） was discussed. A new treatment of inlet boundary was established by discriminating flu...The implementation of high pressure die casting （HPDC） filling process modeling based on smoothed particle hydrodynamics （SPH） was discussed. A new treatment of inlet boundary was established by discriminating fluid particles from inlet particles. The roles of artificial viscosity and moving least squares method in the present model were compared in the handling pressure oscillation. The final model was substantiated by simulating filling process in HPDC in both two and three dimensions. The simulated results from SPH and finite difference method （FDM） were compared with the experiments. The results show the former is in a better agreement with experiments. It demonstrates the efficiency and precision of this SPH model in describing flow pattern in filling process.展开更多
The interfacial heat transfer behavior at the metalJshot sleeve interface in the high pressure die casting （HPDC） process of AZ91D alloy is carefully investigated. Based on the temperature measurements along the sho...The interfacial heat transfer behavior at the metalJshot sleeve interface in the high pressure die casting （HPDC） process of AZ91D alloy is carefully investigated. Based on the temperature measurements along the shot sleeve, inverse method has been developed to determine the interfacial heat transfer coefficient in the shot sleeve. Under static condition, Interracial heat transfer coefficient （IHTC） peak values are 11.9, 7,3, 8.33kWm-2K-1 at pouring zone （S2）, middle zone （S5）, and end zone （510）, respectively. During the casting process, the IHTC curve displays a second peak of 6.1 kWm-2 K-1 at middle zone during the casting process at a slow speed of 0.3 ms 1 Subsequently, when the high speed started, the IHTC curve reached a second peal〈 of 12.9 kW m-2K-1 at end zone. Furthermore, under different slow casting speeds, both the calculated initial temperature （TIDs） and the maximum temperature （Tsimax） of shot sleeve surface first decrease from 0.1 ms-1 to 0.3 ms-1, but increase again from 0.3 ms-1 to 0.6 ms-1. This result agrees with the experimental results obtained in a series of ＂plate-shape＂ casting experiments under different slow speeds, which reveals that the amount of ESCs decreases to the minimum values at 0.3 m s-1 and increase again with the increasing casting slow speed.展开更多
Since the introduction of Tesla's Giga-Casting process, the automotive industry has widely accepted the concept of super-sized structural components due to their significant potential for enhancing the light-weigh...Since the introduction of Tesla's Giga-Casting process, the automotive industry has widely accepted the concept of super-sized structural components due to their significant potential for enhancing the light-weighting of both electric and internal combustion engine vehicles.These super-sized components can be further lightened by using Mg alloys because of their exceptional lightweight characteristics, with a density only two-thirds that of aluminium alloys and one-fourth that of steel. This outstanding attribute offers the attractive prospect of achieving significant weight reduction without compromising structural integrity. This review examines studies on the Mg-alloy HighPressure Die Casting(HPDC) process, providing insights into the future prospects of incorporating Mg alloys into super-sized automotive HPDC components.展开更多
Heat transfer at the metal-die interface has a great influence on the solidification process and casting structure. As thin-wall components are extensively produced by high pressure die casting process(HPDC), the B390...Heat transfer at the metal-die interface has a great influence on the solidification process and casting structure. As thin-wall components are extensively produced by high pressure die casting process(HPDC), the B390 alloy finger-plate casting was cast against an H13 steel die on a cold-chamber HPDC machine. The interfacial heat transfer behavior at different positions of the die was carefully studied using an inverse approach based on the temperature measurements inside the die. Furthermore, the filling process and the solidification rate in different finger-plates were also given to explain the distribution of interfacial heat flux(q) and interfacial heat transfer coefficient(h). Measurement results at the side of sprue indicates that qmax and hmax could reach 9.2 MW·m^(-2) and 64.3 kW ·m^(-2)·K^(-1), respectively. The simulation of melt flow in the die reveals that the thinnest(T_1) finger plate could accelerate the melt flow from 50 m·s^(-1) to 110 m·s^(-1). Due to this high velocity, the interfacial heat flux at the end of T_1 could firstly reach a highest value 7.92 MW·m^(-2) among the ends of T_n(n=2,3,4,5). In addition, the q_(max) and h_(max) values of T_2, T_4 and T_5 finger-plates increase with the increasing thickness of the finger plate. Finally, at the rapid decreasing stage of interfacial heat transfer coefficient(h), the decreasing rate of h has an exponential relationship with the increasing rate of solid fraction(f).展开更多
Flexibility of the CSIR-RCS, induction stirring with simultaneous air cooling process, in combination with high pressure die casting is successfully demonstrated by semi-solid rheocasting of plates performed on commer...Flexibility of the CSIR-RCS, induction stirring with simultaneous air cooling process, in combination with high pressure die casting is successfully demonstrated by semi-solid rheocasting of plates performed on commercial 2024, 6082 and 7075 wrought aluminum alloys. Tensile properties were measured for the above mentioned rheocast wrought aluminum alloys in the T6 condition. The results showed that tensile properties were close to or even in some cases exceeded the minimum specifications. The yield strength and elongation of rheocast 2024-T6 exceeded the minimum requirements of the wrought alloy in the T6 condition but the ultimate tensile strength achieved only 90% of the specification because the Mg content of the starting alloy was below the commercial alloy specification. The strengths of rheocast 6082-T6 exceeded all of the wrought alloy T6 strength targets but the elongation only managed 36% of the required minimum due to porosity, caused by incipient melting during solution heat treatment, and the presence of fine intermetallie needles in the eutectic. The yield strength of rheocast 7075 exceeded the required one and the ultimate tensile strength also managed 97% of the specification; while the elongation only reached 46% of the minimum requirement also due to incipient melting porosity caused during the solution heat treatment process.展开更多
3D reconstruction and 2D observation were conducted to characterize the microstructure of the castings produced through high pressure die casting with different parameters.Our results indicate that shrinkage pores gen...3D reconstruction and 2D observation were conducted to characterize the microstructure of the castings produced through high pressure die casting with different parameters.Our results indicate that shrinkage pores generally co-existed with externally solidified crystals(ESCs).In specimen produced without fast slow shot speed,big net-shrinkage pores accompanied with ESCs were found in the center of the specimen.When the casting pressurization was introduced,the shrinkage pores gathered to the specimen center and became much less due to the optimization of melt feeding.Much more porosity was found near the gate rather than in the middle of the rod bar,especially gas pores.Thefilling process simulation reveals that the middle position of the bars wasfirstlyfilled and followed by the near gate position accompanied with one intense turbulentflow.展开更多
A newly developed Mg-4Zn-2La-3Y alloy with high strength was fabricated by high-pressure die casting method,and its microstructures were thoroughly studied using transmission electron microscopy.The results demonstrat...A newly developed Mg-4Zn-2La-3Y alloy with high strength was fabricated by high-pressure die casting method,and its microstructures were thoroughly studied using transmission electron microscopy.The results demonstrate that it owns fine grains and approximately highly interconnected intermetallic phase skeletons,and exhibits ultra-high strength at both room and high temperatures.Interestingly,the eutectic intermetallic skeleton of this alloys is consisted of numerous fine particles,which are mainly consisted of two intermetallic phases,namely W and Mg12RE.Multiple{101}twins and SFs were found in the Mg12RE phase while a few of SFs in the W phase.Additionally,minor long-period stacking ordered phase was observed in the eutectoid phase,and it probably nucleated on the Mg12RE phase following a certain OR as(0002)14H//(110)Mg12REand[1120]14H//[111]Mg12RE,or(0002)14H//(211)Mg12REand[1120]14H//[111]Mg12RE.This special intermetallic skeleton with many interfaces and planar faults can efficiently transfer dislocations across grain boundaries,and this is the key factor for the outstanding mechanical properties of the studied alloy.展开更多
To understand the relationship between the process-microstructure-mechanical properties of the high-pressure die-casting(HPDC) AE44 magnesium alloy, 3D reconstruction and 2D characterization were carried out on the HP...To understand the relationship between the process-microstructure-mechanical properties of the high-pressure die-casting(HPDC) AE44 magnesium alloy, 3D reconstruction and 2D characterization were carried out on the HPDC castings produced with different process parameters(low slow-shot speed, fast slow-shot speed, solidification pressure). Microstructural characterization revealed that the formation of shrinkage pores are closely related to ESCs, which were mainly controlled by the low slow-shot speed in shot sleeve(ESCs growth time) and fast slow-shot speed into the die cavity(distribution of ESCs). In addition, solidification pressure can significantly reduce the shrinkage porosity in the center by improving the feeding capacity of liquid metal. Tensile fracture revealed that the tearing ridge is mainly evolved from the slip band of ESCs. The quantity and distribution of ESCs determine the fracture mode of castings. The relationship between mechanical properties of castings and the morphology of ESCs and porosity is also statistically discussed.展开更多
The Mg_(17)Al_(12)β-phase is highly influential to the performance of magnesium-aluminum high-pressure die-casting alloys. Numerous studies have investigated the effect of this phase on the room temperature and eleva...The Mg_(17)Al_(12)β-phase is highly influential to the performance of magnesium-aluminum high-pressure die-casting alloys. Numerous studies have investigated the effect of this phase on the room temperature and elevated-temperature mechanical properties as well as the corrosion,flammability, thermal conductivity and castability performance. This work summarizes the results of these works, as well as the studies that describe control of the Mg_(17)Al_(12)-phase through alloying additions that modify the microstructure and resulting alloy performance. The results of this work can be used as a basis for the development of alloying additions that enable modifications to the performance of high-pressure die-cast magnesium-aluminum-based alloys.展开更多
Rheocasting of plates in Al alloy 359 reinforced with SiC at 11%,27% and 50%(volume fractions) exhibits the capability of the council for scientific and industrial research-rheocasting system(CSIR-RCS) in rheo-process...Rheocasting of plates in Al alloy 359 reinforced with SiC at 11%,27% and 50%(volume fractions) exhibits the capability of the council for scientific and industrial research-rheocasting system(CSIR-RCS) in rheo-processing and high pressure die casting of SiC metal matrix composites.The metal matrix consisting of nearly spherical proeutectic α(Al) globules was produced.Spheroidization of fibrous eutectic silicon took place upon heat treatment of the as-cast metal matrix composites(MMCs).Hardness increases as the volume fractions of SiC increases.Wear rates of the MMCs in the F and T6 heat treatment conditions were assessed with a metallographic preparation machine.It is found that the 11% SiC MMC wear rate is higher on SiC abrasives compared with the 50% SiC MMC wear rate due to wear of the aluminum matrix.This trend is reversed on diamond abrasives due to pull-out of the irregular shaped composite particles.The 50% SiC MMC suffers from composite particle fracture porosity after high pressure die casting(HPDC).展开更多
The high pressure die casting (HPDC) process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today's manufacturing industry...The high pressure die casting (HPDC) process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today's manufacturing industry. In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC) was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger, and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified, when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior.展开更多
基金Project (2009Z001) supported by the Important Item in Guangdong-Hong Kong Key Project, ChinaProject (2010B090400297) supported by the Cooperation Project in Industry, Education and Research of Guangdong Province and Ministry of Education of China
文摘The implementation of high pressure die casting （HPDC） filling process modeling based on smoothed particle hydrodynamics （SPH） was discussed. A new treatment of inlet boundary was established by discriminating fluid particles from inlet particles. The roles of artificial viscosity and moving least squares method in the present model were compared in the handling pressure oscillation. The final model was substantiated by simulating filling process in HPDC in both two and three dimensions. The simulated results from SPH and finite difference method （FDM） were compared with the experiments. The results show the former is in a better agreement with experiments. It demonstrates the efficiency and precision of this SPH model in describing flow pattern in filling process.
基金financially supported by the National Major Science and Technology Program of China(No.2012ZX04012011)the National Natural Science Foundation of China(No.51275269)
文摘The interfacial heat transfer behavior at the metalJshot sleeve interface in the high pressure die casting （HPDC） process of AZ91D alloy is carefully investigated. Based on the temperature measurements along the shot sleeve, inverse method has been developed to determine the interfacial heat transfer coefficient in the shot sleeve. Under static condition, Interracial heat transfer coefficient （IHTC） peak values are 11.9, 7,3, 8.33kWm-2K-1 at pouring zone （S2）, middle zone （S5）, and end zone （510）, respectively. During the casting process, the IHTC curve displays a second peak of 6.1 kWm-2 K-1 at middle zone during the casting process at a slow speed of 0.3 ms 1 Subsequently, when the high speed started, the IHTC curve reached a second peal〈 of 12.9 kW m-2K-1 at end zone. Furthermore, under different slow casting speeds, both the calculated initial temperature （TIDs） and the maximum temperature （Tsimax） of shot sleeve surface first decrease from 0.1 ms-1 to 0.3 ms-1, but increase again from 0.3 ms-1 to 0.6 ms-1. This result agrees with the experimental results obtained in a series of ＂plate-shape＂ casting experiments under different slow speeds, which reveals that the amount of ESCs decreases to the minimum values at 0.3 m s-1 and increase again with the increasing casting slow speed.
基金the funding from the National Key R&D Program of China (No.2022YFB3709300 and No.2021YFB3701000)National Natural Science Foundation of China (No.U21A2048,No.52271090,and No.52101125)。
文摘Since the introduction of Tesla's Giga-Casting process, the automotive industry has widely accepted the concept of super-sized structural components due to their significant potential for enhancing the light-weighting of both electric and internal combustion engine vehicles.These super-sized components can be further lightened by using Mg alloys because of their exceptional lightweight characteristics, with a density only two-thirds that of aluminium alloys and one-fourth that of steel. This outstanding attribute offers the attractive prospect of achieving significant weight reduction without compromising structural integrity. This review examines studies on the Mg-alloy HighPressure Die Casting(HPDC) process, providing insights into the future prospects of incorporating Mg alloys into super-sized automotive HPDC components.
基金financially supported by the class General Financial Grant from the China Postdoctoral Science Foundation(No.2015M580093)the National Nature Science Foundation of China(No.20151301587)the National Major Science and Technology Program of China(No.2012ZX04012011)
文摘Heat transfer at the metal-die interface has a great influence on the solidification process and casting structure. As thin-wall components are extensively produced by high pressure die casting process(HPDC), the B390 alloy finger-plate casting was cast against an H13 steel die on a cold-chamber HPDC machine. The interfacial heat transfer behavior at different positions of the die was carefully studied using an inverse approach based on the temperature measurements inside the die. Furthermore, the filling process and the solidification rate in different finger-plates were also given to explain the distribution of interfacial heat flux(q) and interfacial heat transfer coefficient(h). Measurement results at the side of sprue indicates that qmax and hmax could reach 9.2 MW·m^(-2) and 64.3 kW ·m^(-2)·K^(-1), respectively. The simulation of melt flow in the die reveals that the thinnest(T_1) finger plate could accelerate the melt flow from 50 m·s^(-1) to 110 m·s^(-1). Due to this high velocity, the interfacial heat flux at the end of T_1 could firstly reach a highest value 7.92 MW·m^(-2) among the ends of T_n(n=2,3,4,5). In addition, the q_(max) and h_(max) values of T_2, T_4 and T_5 finger-plates increase with the increasing thickness of the finger plate. Finally, at the rapid decreasing stage of interfacial heat transfer coefficient(h), the decreasing rate of h has an exponential relationship with the increasing rate of solid fraction(f).
文摘Flexibility of the CSIR-RCS, induction stirring with simultaneous air cooling process, in combination with high pressure die casting is successfully demonstrated by semi-solid rheocasting of plates performed on commercial 2024, 6082 and 7075 wrought aluminum alloys. Tensile properties were measured for the above mentioned rheocast wrought aluminum alloys in the T6 condition. The results showed that tensile properties were close to or even in some cases exceeded the minimum specifications. The yield strength and elongation of rheocast 2024-T6 exceeded the minimum requirements of the wrought alloy in the T6 condition but the ultimate tensile strength achieved only 90% of the specification because the Mg content of the starting alloy was below the commercial alloy specification. The strengths of rheocast 6082-T6 exceeded all of the wrought alloy T6 strength targets but the elongation only managed 36% of the required minimum due to porosity, caused by incipient melting during solution heat treatment, and the presence of fine intermetallie needles in the eutectic. The yield strength of rheocast 7075 exceeded the required one and the ultimate tensile strength also managed 97% of the specification; while the elongation only reached 46% of the minimum requirement also due to incipient melting porosity caused during the solution heat treatment process.
基金financially supported by the National Natural Science Foundation of China (No. 52175284)the State Key Lab of Advanced Metals and Materials (2021-ZD08)technical support of BL13W1 Beamline in Shanghai Synchrotron Radiation Facility (SSRF) and Gaomi Xiangyu company
文摘3D reconstruction and 2D observation were conducted to characterize the microstructure of the castings produced through high pressure die casting with different parameters.Our results indicate that shrinkage pores generally co-existed with externally solidified crystals(ESCs).In specimen produced without fast slow shot speed,big net-shrinkage pores accompanied with ESCs were found in the center of the specimen.When the casting pressurization was introduced,the shrinkage pores gathered to the specimen center and became much less due to the optimization of melt feeding.Much more porosity was found near the gate rather than in the middle of the rod bar,especially gas pores.Thefilling process simulation reveals that the middle position of the bars wasfirstlyfilled and followed by the near gate position accompanied with one intense turbulentflow.
基金supported by the National Natural Science Foundation of China under grants no.51701200 and 51871069the Scientific and Technological Developing Scheme of Jilin Province under grants no.20200801048GH。
文摘A newly developed Mg-4Zn-2La-3Y alloy with high strength was fabricated by high-pressure die casting method,and its microstructures were thoroughly studied using transmission electron microscopy.The results demonstrate that it owns fine grains and approximately highly interconnected intermetallic phase skeletons,and exhibits ultra-high strength at both room and high temperatures.Interestingly,the eutectic intermetallic skeleton of this alloys is consisted of numerous fine particles,which are mainly consisted of two intermetallic phases,namely W and Mg12RE.Multiple{101}twins and SFs were found in the Mg12RE phase while a few of SFs in the W phase.Additionally,minor long-period stacking ordered phase was observed in the eutectoid phase,and it probably nucleated on the Mg12RE phase following a certain OR as(0002)14H//(110)Mg12REand[1120]14H//[111]Mg12RE,or(0002)14H//(211)Mg12REand[1120]14H//[111]Mg12RE.This special intermetallic skeleton with many interfaces and planar faults can efficiently transfer dislocations across grain boundaries,and this is the key factor for the outstanding mechanical properties of the studied alloy.
基金financially supported by the Fundamental Research Funds for the Central Universities (M22JBMC0060)the National Natural Science Foundation of China (No.52175284)the State Key Lab of Advanced Metals and Materials (No.2021-ZD08)。
文摘To understand the relationship between the process-microstructure-mechanical properties of the high-pressure die-casting(HPDC) AE44 magnesium alloy, 3D reconstruction and 2D characterization were carried out on the HPDC castings produced with different process parameters(low slow-shot speed, fast slow-shot speed, solidification pressure). Microstructural characterization revealed that the formation of shrinkage pores are closely related to ESCs, which were mainly controlled by the low slow-shot speed in shot sleeve(ESCs growth time) and fast slow-shot speed into the die cavity(distribution of ESCs). In addition, solidification pressure can significantly reduce the shrinkage porosity in the center by improving the feeding capacity of liquid metal. Tensile fracture revealed that the tearing ridge is mainly evolved from the slip band of ESCs. The quantity and distribution of ESCs determine the fracture mode of castings. The relationship between mechanical properties of castings and the morphology of ESCs and porosity is also statistically discussed.
文摘The Mg_(17)Al_(12)β-phase is highly influential to the performance of magnesium-aluminum high-pressure die-casting alloys. Numerous studies have investigated the effect of this phase on the room temperature and elevated-temperature mechanical properties as well as the corrosion,flammability, thermal conductivity and castability performance. This work summarizes the results of these works, as well as the studies that describe control of the Mg_(17)Al_(12)-phase through alloying additions that modify the microstructure and resulting alloy performance. The results of this work can be used as a basis for the development of alloying additions that enable modifications to the performance of high-pressure die-cast magnesium-aluminum-based alloys.
文摘Rheocasting of plates in Al alloy 359 reinforced with SiC at 11%,27% and 50%(volume fractions) exhibits the capability of the council for scientific and industrial research-rheocasting system(CSIR-RCS) in rheo-processing and high pressure die casting of SiC metal matrix composites.The metal matrix consisting of nearly spherical proeutectic α(Al) globules was produced.Spheroidization of fibrous eutectic silicon took place upon heat treatment of the as-cast metal matrix composites(MMCs).Hardness increases as the volume fractions of SiC increases.Wear rates of the MMCs in the F and T6 heat treatment conditions were assessed with a metallographic preparation machine.It is found that the 11% SiC MMC wear rate is higher on SiC abrasives compared with the 50% SiC MMC wear rate due to wear of the aluminum matrix.This trend is reversed on diamond abrasives due to pull-out of the irregular shaped composite particles.The 50% SiC MMC suffers from composite particle fracture porosity after high pressure die casting(HPDC).
文摘The high pressure die casting (HPDC) process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today's manufacturing industry. In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC) was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger, and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified, when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior.
