scholarly journals Mechanical Properties and Microstructure Evolution of Aluminum Alloy Tubes with Normal Gradient Grain Under Biaxial Stress

2021 ◽  
Author(s):  
Yang CAI ◽  
Xiaosong Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Aluminum Alloy ◽  
Biaxial Stress ◽  
Maximum Expansion ◽  
Grain Distribution ◽  
Strength And Plasticity ◽  
Hydraulic Bulging ◽  
Aluminum Alloy Tube ◽  
Size Gradient

Abstract Grain size gradient materials are a type of new structural material with the advantages of both coarse and fine grains. To study the effect of normal gradient grain on the mechanical properties and microstructure of aluminum alloy tube during hydroforming, the normal gradient grain distribution of the outer fine and inner coarse grains was obtained using spinning and annealing methods, and the biaxial stress was acquired using hydraulic bulging experiments. The thickness of the outer refined area was 105, 470, and 570 μm, respectively, where the grain size was refined to within 50 μm. Under biaxial stress, the tensile strength of the tube was 79, 89, and 106 MPa, the maximum expansion rates were 18%, 17%, and 10%, and the work-hardening indexes were 0.19, 0.20, and 0.17, respectively. The gradient grain tube with a refined thickness of 470 μm exhibited both strength and plasticity and was suitable for the hydroforming of aluminum alloy tubular parts. With increasing refined grain area, the density of the low angular grain boundary increased and make the chance of stitching dislocation increased in the process of intracranular deformation. However, the increase in the refined region weakened the deformation coordination, leading to a decrease in plasticity.

Effect of In Situ TiB2 Particles on the Grain Size and Mechanical Properties of 7075 Aluminum Alloy

2021 ◽  
Vol 1035 ◽  
pp. 102-107
Author(s):  
Shao Ming Ma ◽  
Chuan Liu Wang ◽  
Yun Lin Fan
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Aluminum Alloy ◽  
High Strength ◽  
Light Weight ◽  
7075 Aluminum Alloy ◽  
Directional Drilling ◽  
High Strength Aluminum Alloy ◽  
Drill Pipes

Light-weight and high-strength aluminum alloy drill pipes are potential and promising to replace traditional steel drill pipes. In this study, the grain size and mechanical properties of aluminum alloy drilling pipe materials reinforced by in-situ TiB2 particles were studied. The results showed when reinforced by in-situ TiB2 particles the grain size of aluminum alloy materials was refined from 155 m to 57 m and ultimate tensile strength was increased from 590 MPa to 720 MPa. Besides, the results also indicated that the friction coefficient was reduced from 0.99 to 0.50 and thus the abrasion resistance of 7075 aluminum alloy was enhanced by 34 %. This study provided theoretical basis for the application of light-weight and high-strength aluminum alloy drill pipes in directional drilling and ultra-deep wells.

scholarly journals Experimental Investigation and Optimization of the Semisolid Multicavity Squeeze Casting Process for Wrought Aluminum Alloy Scroll

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5278
Author(s):  
Yi Guo ◽  
Yongfei Wang ◽  
Shengdun Zhao
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Process Parameters ◽  
Squeeze Casting ◽  
Shrinkage Porosity ◽  
Optimal Process ◽  
Squeeze Pressure ◽  
Wrought Aluminum

Scroll compressors are popularly applied in air-conditioning systems. The conventional fabrication process causes gas and shrinkage porosity in the scroll. In this paper, the electromagnetic stirring (EMS)-based semisolid multicavity squeeze casting (SMSC) process is proposed for effectively manufacturing wrought aluminum alloy scrolls. Insulation temperature, squeeze pressure, and the treatment of the micromorphology and mechanical properties of the scroll were investigated experimentally. It was found that reducing the insulation temperature can decrease the grain size, increase the shape factor, and improve mechanical properties. The minimum grain size was found as 111 ± 3 μm at the insulation temperature of 595 °C. The maximum tensile strength, yield strength, and hardness were observed as 386 ± 8 MPa, 228 ± 5 MPa, and 117 ± 5 HV, respectively, at the squeeze pressure of 100 MPa. The tensile strength and hardness of the scroll could be improved, and the elongation was reduced by the T6 heat treatment. The optimal process parameters are recommended at an insulation temperature in the range of 595–600 °C and a squeeze pressure of 100 MPa. Under the optimal process parameters, scroll casting was completely filled, and there was no obvious shrinkage defect observed inside. Its microstructure is composed of fine and spherical grains.

Effects of Pulsed Magnetic Field on the Microstructure and Mechanical Properties of Mg97Y2Zn1 Alloy

2014 ◽  
Vol 1004-1005 ◽  
pp. 123-126 ◽  
Author(s):  
Jian Yin ◽  
Xiu Jun Ma ◽  
Jun Ping Yao ◽  
Zhi Jian Zhou
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Grain Size ◽  
Volume Fraction ◽  
Pulsed Magnetic Field ◽  
Second Phase ◽  
Microstructure And Mechanical Properties ◽  
Magnetic Field Treatment ◽  
Semi Solid ◽  
Strength And Plasticity

Effect of pulsed magnetic field treatment on the microstructure and mechanical properties of Mg97Y2Zn1 alloy has been investigated. When the pulsed magnetic field is applied on the alloy in semi-solid state, the α-Mg was modified from developed dendrite to fine rosette, resulting in a refined solidification microstructure with the grain size decreased from 4 mm to 0.5 mm. The volume fraction of the second phase ( X phase) increased by about 10 %. The yield strength, fracture strength and plasticity were improved by 21 MPa, 38 MPa and 2.4 %, respectively. The improvement of mechanical properties was attributed to the refined grain size and increased volume fraction of X phase.

Effects of annealing treatment on mechanical properties of 8011 aluminum alloy after cryogenic rolling

2019 ◽  
Vol 116 (2) ◽  
pp. 219 ◽  
Author(s):  
Junjun Cui ◽  
Liqing Chen ◽  
Yanfei Li ◽  
Jiahua Liu ◽  
Jiaqi Xie
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Grain Size ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Annealing Treatment ◽  
Energy Dispersive Spectrum ◽  
Second Phase ◽  
Cryogenic Rolling ◽  
The Ideal

In order to improve mechanical properties of roll cast 8011 aluminum alloy (AA 8011) by grain strengthening, and expand its application field, the effect of different annealing treating processes on mechanical properties and microstructures of cryogenic rolled AA 8011 was investigated. The roll cast AA 8011 was cryogenic rolled for six passes and then annealed. The annealing treatment was adopted at 100–300 °C for 1 h, and then the annealing treatment was adopted at 220 °C for 10–80 min. The microstructures of AA 8011 under roll cast and cryogenic rolled states were studied by using OM. The grain size was calculated by the Image-pro-plus 5.0. The microstructures of AA 8011 under annealing states were observed by using TEM and energy dispersive spectrum analysis. The results show that the second phase Al8Fe2Si appears in the cryogenic rolled AA 8011 after annealing treatment. When the dislocation moves in the grain, the dislocation plays a pinning role, which is conducive to grain refinement. The optical annealing treatment was treated at 220 °C for 40 min with optimal thermal stability. The ideal grain size is 1 μm, hardness is 65 HV, and tensile strength is 202 MPa. It is about 1.5 times of the roll cast AA 8011.

Effect of Melt Purification on Microstructure and Mechanical Properties of 3003 Aluminum Alloy

2018 ◽  
Vol 921 ◽  
pp. 262-268
Author(s):  
Gui Qing Chen ◽  
Gao Sheng Fu ◽  
Jun De Wang ◽  
Kai Huai Yang ◽  
Shao Yi Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Impurity Content ◽  
Aluminum Melt ◽  
Microstructure And Mechanical Properties ◽  
Alloy Strength ◽  
Dispersed Inclusions ◽  
Strength And Plasticity

The 3003 aluminum alloy melt was treated with three types of melt purification, and the effect of melt purification on the microstructure and mechanical properties of the alloy was investigated. The results show that the impurity content of 3003 aluminum alloy with untreated (UT) reached 0.6801 %. After the process of conventional purification treatment (CPT) and efficient purification treatment (EPT), the impurity content of the alloy decreased significantly, and the fluidity of aluminum melt was improved. Finely dispersed inclusions particles can promote nucleation, refine the size of the cast crystal. Alloy strength and plasticity have increased using the process of CPT and EPT, in particular, EPT is the most obvious. It shows that the purity of aluminum melt plays a key role in the mechanical properties of the alloy.

scholarly journals Experimental Studies on Cracking and Local Strain Behaviors of Rock-Like Materials with a Single Hole before and after Reinforcement under Biaxial Compression

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jian Liao ◽  
Yanlin Zhao ◽  
Liming Tang ◽  
Qiang Liu
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Failure Modes ◽  
Lateral Pressure ◽  
Peak Strength ◽  
Biaxial Compression ◽  
Tensile Cracks ◽  
Fracture Surfaces ◽  
Single Hole ◽  
Aluminum Alloy Tube

In deep underground engineering, circular roadways are widely used; many rock engineering problems can usually be simplified as mechanical analysis of rock structures with holes. To reveal the influence of intrahole reinforcement on the mechanical properties of rock with a single hole, this paper takes the single-hole rock-like material specimens with different reinforcement conditions as the research object. The RYL600 rock shear rheometer was used to conduct biaxial compression tests and, combined with HD industrial cameras and high-precision strain gauges, to study the effects of different reinforcement thicknesses and different lateral pressure on the mechanical properties of single-hole rock-like materials during the total stress and strain process. The thickness of the reinforced aluminum alloy pipe in the whole test is divided into four types: 0, 1, 1.5, and 2 mm. Under different reinforcement conditions, it is divided into 4 series of 0, 0.5, 1, and 1.5 MPa according to the different lateral pressure. Research shows the following: (1) Under the same lateral pressure, as the reinforcement thickness of the aluminum alloy tube increases, the reinforcement effect of the aluminum alloy tube on the specimen increases, and the strength of the reinforced specimen is increased by 1.42%~33.04% compared with the strength of the unreinforced specimen; under the same reinforced thickness of the aluminum tube, the peak strength of the specimen increases with the increase of lateral pressure, and the peak strength of the specimen with lateral pressure is 3.34%~50.26% higher than that of the specimen without lateral pressure. (2) Increasing the lateral pressure can significantly reduce the primary tensile cracks of the specimen. As the reinforcement thickness increases, the primary tensile cracks and remote cracks of the specimen are significantly reduced, and the failure surface of the specimen gradually tends to the middle of the sample. (3) The failure modes of specimens with holes can be divided into five types: single bevel type I, single bevel type II, single bevel type III, bevel T type, and single part shear type. All of these five failure modes are shear cracks that develop into fracture surfaces, while remote cracks and primary tensile cracks do not develop into fracture surfaces.

scholarly journals Effect of Sc on the Hot Cracking Properties of 7xxx Aluminum Alloy and the Microstructure of Squeeze Castings

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6881
Author(s):  
Yongtao Xu ◽  
Zhifeng Zhang ◽  
Zhihua Gao ◽  
Yuelong Bai ◽  
Purui Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Aluminum Alloy ◽  
Performance Test ◽  
Casting Process ◽  
Hot Cracking ◽  
Hot Tearing ◽  
Average Grain Size ◽  
Cylindrical Parts ◽  
Series Aluminum Alloy

In this paper, the effect of adding the refiner Sc to the high Zn/Mg ratio 7xxx series aluminum alloy melt on the hot tearing performance, microstructure, and mechanical properties of the alloy is studied. The hot tearing performance test (CRC) method is used to evaluate the hot tearing performance of the alloy. The squeeze casting process was used to form solid cylindrical parts to analyze the structure and properties of the alloy. This study shows that the hot cracking sensitivity of the alloy after the addition of the refiner Sc is significantly reduced. The ingot grain size is significantly reduced, and the average grain size is reduced from about 86 μm to about 53 μm. While the mechanical properties are significantly improved, and the tensile strength reduced from 552 MPa is increased to 571 MPa, and the elongation rate is increased from 11% to 14%.

Research on the Strength Improvement of 7A04 Aluminum Alloy

2012 ◽  
Vol 488-489 ◽  
pp. 19-21
Author(s):  
Chao Jue Yi ◽  
Peng Cheng Zhai ◽  
Li Zhou Dong ◽  
Qi Hao Fu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Grain Refinement ◽  
Cryogenic Treatment ◽  
The Impact ◽  
Strength Improvement

By using cryogenic treatment on 7A04 aluminum alloy tested with micrographic analysis and mechanical properties test, we studied the impact on mechanical properties of 7A04 aluminum alloy The results showed that the strength of 7A04 aluminum alloy could be highly increased and the grain size would be reduced in the process through being treated in 480°C/80min + aging in 120°C/4h + cryogenic treatment + aging at 120°C/16h.7A04 aluminum alloy are more fully recrystallized to grain refinement and the tensile strength of it can be increased to 720Mpa after the treatment.

scholarly journals Fabrication And Mechanical Properties Of A Nanostructured Complex Aluminum Alloy By Three-Layer Stack Accumulative Roll-Bonding

2015 ◽  
Vol 60 (2) ◽  
pp. 1195-1198 ◽  
Author(s):  
S.-H. Lee ◽  
S.R. Lee
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Aluminum Alloy ◽  
Accumulative Roll Bonding ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet ◽  
Roll Bonding ◽  
Complex Aluminum ◽  
Processed Material ◽  
Layered Complex

Abstract A multi-layered complex aluminum alloy was successfully fabricated by three-layer stack accumulative roll bonding(ARB) process. The ARB using AA1050 and AA5052 alloy sheets was performed up to 7 cycles at ambient temperature without lubrication. The specimen processed by the ARB showed a multi-layer aluminum alloy sheet in which two aluminum alloys are alternately stacked. The grain size of the specimen decreased with the number of ARB cycles, became about 350nm in diameter after 7cycles. The tensile strength increased with the number of ARB cycles, after 6c it reached 281MPa which is about twice higher than that of the starting material. The microstructures and mechanical properties of a three-layer AA1050/AA5052 alloy fabricated by the ARB were compared to those of the conventional ARB-processed material.

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