Semi-Solid 6061 Aluminum Alloy Slurry Prepared by Serpentine Channel Pouring Process and its Rheo-Diecasting

2022 ◽  
Vol 327 ◽  
pp. 279-286
Author(s):  
Nai Yong Li ◽  
Wei Min Mao ◽  
Xiao Xin Geng ◽  
Peng Yu Yan

Semi-solid 6061 aluminum alloy slurry was prepared by a graphite serpentine channel and its rheo-diecasting experiment was carried out on the slurry. The influence of pouring temperature on the microstructure evolution and mechanical properties of the rheo-diecasting were investigated. The microstructure and fracture mechanism of traditional die cast tensile specimens and rheo-diecast tensile specimens were compared and investigated. The results indicate that the microstructure of rheo-diecast tensile specimens is composed of spherical primary α-Al grains and fine secondary solidified α2-Al grains. When the pouring temperature increased from 660 °C to 720 °C, the average equivalent grain diameter of primary α-Al grains increased from 42 μm to 58 μm, and the shape factor decreased from 0.82 to 0.73. As the pouring temperature increases, the as-cast tensile strength and elongation of tensile specimens both increase first and then decrease. When the pouring temperature was 690 °C, the best mechanical properties were obtained, with as-cast tensile strength of 142.93 MPa and as-cast elongation of 4.86%. The fracture mechanism of traditional die casting is mainly ductile fracture, and the fracture mechanism of rheo-diecasting is a mixed fracture of intergranular fracture and ductile fracture.

2022 ◽  
Vol 327 ◽  
pp. 255-262
Author(s):  
Nai Yong Li ◽  
Wei Min Mao ◽  
Xiao Xin Geng ◽  
Peng Yu Yan

The semi-solid slurry of 6061 aluminum alloy was prepared by the serpentine channel pouring process. The influence of graphite serpentine channel and copper serpentine channel on the slurry was comparative analyzed. The effect of pouring temperature on the slurry microstructure was also investigated. The results indicate that both copper and graphite serpentine channel can be used to prepare semi-solid slurry with spherical primary grains. Compared with a permanent casting, the microstructure of the semi-solid slurry was significantly improved and refined. With the increase of pouring temperature, the average equivalent grain diameter of the primary phase grains in the semi-solid slurry increases gradually, but the shape factor decreases gradually. When the pouring temperature increased from 675 °C to 690 °C, a high quality semi-solid slurry can be obtained. Comparing the two kinds of serpentine channel, it is found that the copper serpentine channel can make the primary grains finer, and the average equivalent grain size was 63 μm. However, the solidified shell near the inner graphite serpentine channel surface was thinner than that of the copper serpentine channel. In conclusion, the graphite serpentine channel is more suitable for preparing semi-solid 6061 aluminum alloy slurry.


2015 ◽  
Vol 651-653 ◽  
pp. 1569-1574 ◽  
Author(s):  
Asnul Hadi Ahmad ◽  
Sumsun Naher ◽  
Dermot Brabazon

Abstracts: This paper presents an overview of measured mechanical properties of thixoformed aluminium 7075 feedstock produced by the direct thermal method (DTM). The DTM feedstock billets were processed with a pouring temperature of 685 °C and holding periods of 20 s, 40 s and 60 s before being quenched and subsequently thixoformed. A conventionally cast feedstock billet was produced with a pouring temperature of 685 °C and was allowed to solidify without quenching. The feedstock billets were later formed by an injection test unit in the semi-solid state. Tensile testing was then conducted on the thixoformed feedstock billets. Tensile properties for 7075 DTM thixoformed feedstock billets were found significantly influenced by the thixoformed component density. Samples with longer holding times were found to have higher density and higher tensile strength.


2014 ◽  
Vol 680 ◽  
pp. 11-14
Author(s):  
Ke Ren Shi ◽  
Sirikul Wisutmethangoon ◽  
Jessada Wannasin ◽  
Thawatchai Plookphol

In this study, semi-solid Al-Mg-Si alloy (AC4C) was produced by using the Gas Induced Semi-Solid (GISS) die casting process. The tensile strength and ductility of the semi-solid die cast Al alloy (GISS-DC) after T6 heat treatment were investigated and compared with those of the conventional liquid die casting (CLDC). The microstructures of GISS-DC and CLDC observed by an optical microscopy were presented. The ultimate tensile strength (UTS) and yield strength (0.2% YS) of GISS-DC are compatible with those of the CLDC. However, the GISS-DC has better ductility than the CLDC, this may be due to the smaller and more globular primary α-Al phase and rounder shaped-Si particle microstructures presented in the GISS-DC. Common shrinkage pores and defects were also observed by SEM from the fracture surfaces of both alloys.


2016 ◽  
Vol 877 ◽  
pp. 39-44
Author(s):  
Si Min Lei ◽  
Li Gao ◽  
Yohei Harada ◽  
Shinji Kumai

The present work deals with the relationship between microstructure and mechanical properties of A356 aluminum alloy which was produced via thixocasting process under different casting conditions. Feedstock billets were heated to a target temperature to obtain a semi-solid slurry with the required solid fraction. Some billets were heated to a fully-melted condition. In order to obtain fine and spheroidized Al grains, some billets for the partially melting were compressed axially by 33% at a room temperature before heating. The completely-melted and partially-melted slurries were die-cast by using a die-cast machine, and hour glass-shaped rod-type tensile specimens and small-size plate-type tensile specimens were obtained. Small cubic specimens were also collected from the die-cast products for microstructural evaluation. They were polished, and etched by Weck’s reagent. The partially-melted specimen which was compressed before heating shows the spherical Al grains. But the grain of the strain-free partially-melted specimen exhibited complicated morphology. The fully-melted specimen shows the fine and dendrite structure.


2014 ◽  
Vol 788 ◽  
pp. 215-222
Author(s):  
Yong Peng ◽  
Shun Cheng Wang ◽  
Hai Tao Zhou ◽  
Kai Hong Zheng ◽  
He Xing Chen

The effect of applied forging pressure on microstructure and mechanical properties of 6061 aluminum alloy was examined. The results showed that the ultimate tensile strength, elongation and hardness of the alloy after heat-treated treatment increase with the applied forging pressure, and the corresponding highest values, 365MPa, 11.52% and 146.53HV, were obtained at the applied forging pressure of 120MPa. Compared to casting condition without forging pressure, the ultimate tensile strength, elongation and hardness can be increased by 22.8%, 98.2% and 48.7%, respectively. The defects such as the shrinkage pores and cracks were absent in the microstructure due to the applied forging pressure. The SEM observation indicated that the fracture mode of 6061 aluminum alloy is more ductile at higher applied forging pressure.


2020 ◽  
Vol 17 (2) ◽  
pp. 197
Author(s):  
Syaharuddin Rasyid ◽  
Abram Tangkemanda ◽  
Muh. Hasmar Hasbullah ◽  
Muh. Andra Al-Fandi

This study aims to analyze the effect of the stirrer model, stirring rotation (400, 500, 600 rpm), for 20 seconds, and pouring temperature (565, 570, and 5750C) on the microstructure and mechanical properties of the aluminum alloy ADC12. The methods of research are a) preparing material aluminum alloy ADC12, b) making molds, c) casting, d) making specimens for testing, e) micro structure testing and hardness testing, f) analyzing data using Microsoft excel applications. Results of the study show that the smallest grain size occurs in casting parameters: stirrer angle 00, 600 rpm rotation, and pouring temperature 5650C with a value of 27.715 µm. The biggest shape factor occurs in casting parameters: stirrer angle 00, rotation 600 rpm, and pouring temperature 5650C with a value 0.76. The highest hardness occurs in casting parameters: stirrer angle 00, rotation 600 rpm, and pouring temperature 5650C with a value 88.0 HB.


2014 ◽  
Vol 893 ◽  
pp. 353-356
Author(s):  
Atchara Sangchan ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin ◽  
Sirikul Wisutmethangoon

Effect of strontium (Sr) addition on the microstructure and the mechanical properties of semi-solid A356 aluminum alloy produced by GISS process were investigated in this study. Strontium addition resulted in both grain refinement and modification of eutectic Si. The maximum average ultimate tensile strength and elongation of 291.06 MPa and 17.31%, respectively, were obtained from the T6 heat-treated specimen containing 0.08wt%Sr. The excessive addition of strontium (0.2wt%Sr), however, seemed to deteriorate the mechanical properties of the alloy as a result of the Al2Si2Sr particle formation.


2013 ◽  
Vol 313-314 ◽  
pp. 67-71 ◽  
Author(s):  
Nitikarn Pajaroen ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin ◽  
Sirikul Wisutmethangoon

The influence of solution heat treatment (SHT) temperature and time on the microstructure and mechanical properties of semi-solid 6061 aluminum alloy has been investigated in this study. Microstructure of the as-cast 6061 aluminum alloy mainly consisted of globular α-Al matrix and eutectic phase (α-Al + Mg2Si) at the grain boundary (GB). Iron rich intermetallic phase was also observed at the grain boundary. Eutectic phase started to dissolve after solution heat treatment. The dissolution of eutectic phase increased with increasing solution treatment time, however, the amount of remaining eutectic phase was found to be slightly changed after solution treating longer than 1 h at 550 °C and 2 h at 530 °C. Hardness and tensile results of specimens after artificial aging were utilized to compare and select the optimum solution heat treatment condition cooperating with the microstructural observation. The optimum solution heat treatment condition of the alloy in this study was at 530 °C for 2 h.


Author(s):  
Mukesh Kumar ◽  
Muhammad Moazam Baloch ◽  
Muhammad Ishaque Abro ◽  
Sikandar Ali Memon ◽  
Ali Dad Chandio

Aluminum alloys have been attracted by several engineering sectors due to their excellent strengthweight ratio and corrosion resistant properties. These are categorized into 1, 2, 3, 4, 5, 6, 7and 8xxx on the basis of alloying elements. Among these 6xxx series contains aluminum–magnesium–silicon as alloying elements and are widely used in extruded products and automotive body panels. The major advantages of these alloys are good corrosion resistance, medium strength, low cost, age hardening response no yield point phenomenon and Ludering. 6xxx series alloys generally have lower formability than other aluminum alloys which restrict their utilization for wide applications. Keeping in view of the shortcomings in the set of mechanical properties of 6xxx series the efforts were made to improve the tensile strength and toughness properties through age hardening. In present study heat treatment cycles were studied for 6061 aluminum alloy. Three different age hardening temperatures 160, 200 and 240oC were selected. The obtained results showed that 17.26, 7.69, and 10.51% improvement in tensile strength, toughness and hardness respectively was achieved with solution treatment at 380oC followed by an aging 240oC. Microstructural study revealed that substantial improvements in the mechanical properties of 6061 aluminum alloy under heat treatment were achieved due to precipitation of Mg2Si secondary phase.


Alloy Digest ◽  
2000 ◽  
Vol 49 (1) ◽  

Abstract Kaiser Aluminum Alloy 7050 has very high mechanical properties including tensile strength, high fracture toughness, and a high resistance to exfoliation and stress-corrosion cracking. The alloy is typically used in aircraft structural parts. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fracture toughness and fatigue. It also includes information on forming, heat treating, machining, and joining. Filing Code: AL-366. Producer or source: Tennalum, A Division of Kaiser Aluminum.


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