scholarly journals Effects of grain size and dendrite arm spacing on tensile properties of continuous-cast 6061 aluminum alloy billets.

1997 ◽  
Vol 47 (2) ◽  
pp. 98-103 ◽  
Author(s):  
Tomokazu YAMASHITA ◽  
Tooru WATANABE ◽  
Kou NAKAHIRA ◽  
Kenji MATSUDA ◽  
Hiroshi ANADA ◽  
...  
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Tensile Properties ◽  
Continuous Cast ◽  
6061 Aluminum Alloy ◽  
Dendrite Arm Spacing

Effects of Residual Stresses and the Post Weld Heat Treatments of TIG Welded Aluminum Alloy AA6061-T651

2012 ◽  
Author(s):  
Mohammad W. Dewan ◽  
Jiandong Liang ◽  
M. A. Wahab ◽  
Ayman M. Okeil
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Residual Stresses ◽  
Tensile Properties ◽  
Ultrasonic Testing ◽  
Micro Hardness ◽  
Weld Defects ◽  
Performance Reduction ◽  
Weld Heat

Heat treatable AA-6061 T651 Aluminum alloys (Al-Mg-Si) have found considerable importance in various structural applications for their high strength to weight ratio and corrosion resistance properties. Weld defects, residual stresses, and microstructural changes are the key factors for the performance reduction as well as failure of welded structures. Tungsten inert gas (TIG/GTAW) welding was carried out on AA-6061 T651 Aluminum Alloy plates using Argon/Helium (50/50) as the shielding gas. Non-destructive phased array ultrasonic testing (PAUT) was applied for the detection and characterization of weld defects and characterization of the mechanical performances. In this study, ultrasonic technique was also used for the evaluation of post-weld residual stresses in welded components. The approach is based on the acoustoelastic effect, in which ultrasonic wave propagation speed is related to the magnitude of stresses present in the materials. To verify the estimated residual stresses by ultrasonic testing, hole-drilling technique was carried out and observed analogous results. The effects of post weld heat treatment (PWHT) on the residual stresses, grain size, micro hardness, and tensile properties were also studied. The grain size and micro hardness were studied through Heyn’s method and Vickers hardness test, respectively. Lower residual stresses were observed in post-weld heat-treated specimens, which also experienced from microstructure and micro hardness studies. The PWHT also resulted enhanced tensile properties for the redistribution of microstructures and residual stresses.

scholarly journals Effect of Cooling Rate on Microstructure and Properties of Twin-Roll Casting 6061 Aluminum Alloy Sheet

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1168 ◽  
Author(s):  
Zhen Xu ◽  
Sixue Wang ◽  
Hongbin Wang ◽  
Hua Song ◽  
Shengli Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Cooling Rate ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet ◽  
6061 Aluminum Alloy ◽  
Microstructure And Properties ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Twin Roll

In this study, a twin-roll casting sheet of 6061 aluminum alloy was cooled using furnace, asbestos, air, wind and water. The effect of cooling rate on the microstructure and properties of twin-roll casting 6061 aluminum alloy sheet were studied. Optical microscope, scanning electron microscope, X-ray diffraction, microhardness tester and universal tensile machine were used to observe the microstructure and properties of twin-roll casting sheet of 6061 aluminum alloy. The results show that the higher the cooling rate, the smaller the grain size of the alloy and the smaller the number of precipitated phases in the matrix. Uniform grain size of the alloy could be obtained at a stable cooling rate. The hardness, tensile strength and elongation of the twin-roll casting sheet increased with cooling rate. Under wind cooling condition, the twin-roll casting sheet demonstrated excellent comprehensive performance, i.e., 88 MPa of yield strength, 178 MPa of tensile strength and 15% of elongation, respectively. A quantitative Hall–Petch relation was established to predict the yield strength of 6061 twin-roll casting sheets with different grain sizes and cooling rate.

Effect of Solidification Pressure on Secondary Dendrite Arm Spacing of Aluminum Alloy

2011 ◽  
Vol 117-119 ◽  
pp. 1522-1525
Author(s):  
Qing Song Yan ◽  
Xun Zou ◽  
Bo Wen Xiong ◽  
Gang Lu ◽  
Shou Yin Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Casting Process ◽  
Gravity Casting ◽  
Secondary Dendrite Arm Spacing ◽  
Dendrite Arm Spacing ◽  
Feeding Force ◽  
Alloy Castings ◽  
Effect Of Feeding ◽  
Solidification Pressure

The solidification pressure is one of the most important factors in the counter-gravity casting process. Through testing and analyzing the microstructures of aluminum alloy castings under different solidification pressure, the effect of different solidification pressure on the secondary dendrite arm spacing and grain size is studied. The results show that with the increase of the solidification pressure, the secondary dendrite arm spacing and the grain size of aluminum alloy decreases. When the solidification pressure is 250 KPa, the secondary dendrite arm of aluminum alloy is thick, the SDAS is 37.9μm, but when the solidification pressure increases to 450 KPa, the refinement of grain is obviously, and the SDAS is 20.7μm, which is reduced by 45.3% comparing to solidification under 250 KPa. Moreover, when solidification pressure higher, the effect of feeding force becomes more evident, and the dendrite is broken when the feeding force higher than the strength of dendrite. Therefore, the grain size becomes more and more uniform and thin, and the (SDAS) of aluminum alloy are more and more small.

scholarly journals The Effect of pre-aging treatments on Tensile Properties and Hardness for Aluminum Alloys

2019 ◽  
Vol 26 (4) ◽  
pp. 98-104
Author(s):  
Mahmoud AlAssaad ◽  
Mohamad Yehea Al nefawy
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Tensile Properties ◽  
Artificial Aging ◽  
6061 Aluminum Alloy ◽  
One Stage ◽  
Different Temperatures ◽  
One Step ◽  
Hardness Values

Abstract— In this research the effect of artificial aging on tensile strength and hardness for Al-Mg-Si (6061 Aluminum alloy) was study, samples from 6061 alloy were submitted to one step artificial aging for different temperatures, while others samples were submitted to two steps artificial aging (where there is a first stage as pre-aging) in descending and ascending modes. The results showed that the highest tensile strength values were reached 214.7 [N/mm2] and hardness were reached 220 [HB] for 6061 Aluminum alloy when the samples were treated by one-step ageing in 190 [°C] for 3 [hour]. While tensile strength and hardness values of samples treated by two-step ageing were slightly higher than these values when the samples was aged at one stage. Where the maximum values of tensile strength was 215 [N/mm2] and for hardness was 227 [HB] when the 6061 alloy treated with two-step ageing the first one in 175 [°C] for 2 [hour] and the second one in 205 [°C] for 1 [hour].

Effect of Serpentine Channel Pouring Process on the Microstructure of Semi-Solid 6061 Aluminum Alloy Slurry

2022 ◽  
Vol 327 ◽  
pp. 255-262
Author(s):  
Nai Yong Li ◽  
Wei Min Mao ◽  
Xiao Xin Geng ◽  
Peng Yu Yan
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Shape Factor ◽  
Primary Phase ◽  
High Quality ◽  
Pouring Temperature ◽  
6061 Aluminum Alloy ◽  
Serpentine Channel ◽  
Channel Surface ◽  
Semi Solid

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.

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