Influence of Yb Modification on the Microstructure and Mechanical Properties of A356.2 Aluminum Alloy

2017 ◽  
Vol 898 ◽  
pp. 259-264 ◽  
Author(s):  
Shao Chen Zhang ◽  
Jin Feng Leng ◽  
Chen Xue Li ◽  
Xin Ying Teng

A356.2 aluminum alloy (Al–7Si–0.35Mg) has been widely used in automotive and aircraft industries. Previous studies found that the metamorphism effect of rare earth is better than other type of elements because of long modification time and good stability. The influence of Yb addition (0%, 0.2%, 0.4% and 0.6%) and T6 heat treatment on A356.2 alloy has been investigated in this work. The microstructures and mechanical properties of the specimen after T6 treatment were examined by optical microscope, scanning electronic microscope and tensile tests. Experimental results showed that Yb could reduce the size of α-Al and change the Si morphology from needle-like to fine spheroidal particles. With the increase of Yb content, the ultimate tensile strength increased gradually. When adding 0.4%Yb, the alloy achieved the highest ultimate tensile strength (252 MPa) and hardness (97.3HB), 10.12% and 37.66% higher than the alloy with no Yb addition. Tensile fracture analysis showed that the fracture mechanism for A356.2 aluminum alloy after T6 treatment is transgranular/intergranular mixed mode of fracture.

2013 ◽  
Vol 829 ◽  
pp. 583-588 ◽  
Author(s):  
Ali Dalirbod ◽  
Yahya A. Sorkhe ◽  
Hossein Aghajani

Alumina dispersion hardened copper-base composite was fabricated by internal oxidation method. The high temperature tensile fracture of Cu-Al2O3 composite was studied and tensile strengths were determined at different temperatures of 600, 680 and 780 °C. Microstructure was investigated by means of optical microscope and field emission scanning electron microscope (FESEM) with energy dispersive spectroscopy (EDS). Results show that, ultimate tensile strength and yield strength of copper alumina nanocomposite decrease slowly with increasing temperature. The yield strength reaches 119 MPa and ultimate tensile strength reaches 132 MPa at 780 °C. Surface fractography shows a dimple-type fracture on the fracture surface of the tensile tests where dimple size increases with increasing testing temperature and in some regions brittle fracture characteristics could be observed in the fracture surface.


2013 ◽  
Vol 749 ◽  
pp. 105-111
Author(s):  
Wei Yan ◽  
Yuan Hui Weng ◽  
Zong Qiang Luo ◽  
Wei Wen Zhang

The microstructures and mechanical properties of the Cu-17Ni-3Al-X alloy extruded at different temperatures were investigated by hardness and tensile tests, optical microscope and scanning electronic microscope. The experimental results showed that dynamic re-crystallization occured during the hot extrusion at 1000 . The grain size of the extruded alloy was significantly refined and the mechanical properties increased remarkably compared to the as-cast alloy. The alloy extruded at 1075 exhibited good mechanical properties with tensile strength of 994 MPa, Brinell hardness of 296 and elongation of 8.0%, which are 30%, 9% and 285% higher than that of the as-cast alloy.


2011 ◽  
Vol 365 ◽  
pp. 98-103
Author(s):  
De Quan Shi ◽  
Gui Li Gao ◽  
Zhi Wei Gao ◽  
Yan Liu Wang ◽  
Xu Dong Wang

The influence of Al-10RE addition, holding time and holding temperature on the microstructures and mechanical properties of ZL203 aluminum alloy has been studied respectively through using the optical microscope and the universal mechanical testing machine. The experimental results lead to the following conclusions. When Al-10RE addition is 1.0%-1.5%, the holding time is 15 minutes and the holding temperature is 730°C-750°C, the microstructure of Zl203 is perfect. With the increase of Al-10RE addition, the mechanical properties including tensile strength, elongation rate and hardness gradually increase. When the Al-10RE addition is 1.0%-1.5%, the mechanical properties reaches maximum. When the Al-10RE addition is above 1.5%, the mechanical properties decrease with the increase of Al-10RE addition.


2013 ◽  
Vol 744 ◽  
pp. 339-344 ◽  
Author(s):  
Meng Xiang Liu ◽  
Jian Mei Chen

By using some types of means such as Optical Microscope (OM), Scanning Electron Microscopy(SEM), the testing of tensile mechanical properties and the testing of friction and wear, the impacts of the Al-5Ti-1B and Al-20Sr modification on the Al-16Si-4Cu-0.5Mg-0.2Mn alloy microstructure, mechanical properties and friction properties are researched. The results turn out that the modification can significantly refine the primary silicon and the eutectic silicon in the alloy, the Al-5Ti-1B mainly refined the primary silicon in the alloy, the Al-20Sr refined the eutectic silicon; the alloy’s effect of refinement after compound modification is better than that in separate metamorphism. Modification can improve the tensile strength and elongation of the alloy: the tensile strength of the alloy has been increased by 65MPa after its compound modification; also the elongation by 0.4%. Modification can improve wear-resisting property of the alloy and also its effect of compound modification is better than that of separate metamorphism. The modification mechanism of Al-5Ti-1B is that Al3Ti and TiB2 belongs to heterogeneous nucleation; while the modification mechanism of Al-20Sr is that the strontium changes the growth pattern of Si phase.


2012 ◽  
Vol 472-475 ◽  
pp. 707-711
Author(s):  
Guan Lu ◽  
Ya Qin Yang ◽  
Bao Cheng Li ◽  
Zhi Min Zhang

In this paper, the effects of hot extrusion and T5、T6 heat treatment on the microstructures and mechanical properties of ZK60 magnesium alloys are investigated by optical microscope, electronic scanning microscope and mechanical testers. The result shows that both the tensile strength and the elongation of the ZK60 alloy extruded at 380°Care much higher than that of the as-cast alloys, as there are much granular second phases precipitated during the extrusion. The tensile strength of the extruded and T5 treated alloy increases while the elongation decreases faster than that of the extruded alloy. The strengthening effect of the T6 treatment is inferior to that of the T5 treatment. The tensile fracture of the as-cast alloy is brittle fractured while that of the extruded and T5 treated alloy is ductile fractured with lots of deep and even dimples.


2021 ◽  
Vol 2 (12 (110)) ◽  
pp. 22-31
Author(s):  
Agus Widyianto ◽  
Ario Sunar Baskoro ◽  
Gandjar Kiswanto ◽  
Muhamad Fathin Ginanjar Ganeswara

Orbital pipe welding was often used to manufacture piping systems. In orbital pipe welding, a major challenge is the welding torch’s position during the welding process, so that additional methods are needed to overcome these challenges. This paper discusses the influence of welding sequence and welding current on distortion, mechanical properties and metallurgical observations in orbital pipe welding with SS 316L pipe square butt joints. The variation of the orbital pipe welding parameters used is welding current and welding sequence. The welding current used is 100 A, 110 A, and 120 A, while the welding sequence used is one sequence, two sequences, three sequences, and four sequences. The welding results will be analyzed from distortion measurement, mechanical properties test and metallurgical observations. Distortion measurements are made on the pipe before welding and after welding. Testing of mechanical properties includes tensile tests and microhardness tests, while metallurgical observations include macrostructure and microstructural observations. The results show that maximum axial distortion, transverse distortion, ovality, and taper occurred at a welding current of 120 A with four sequences of 445 µm, 300 µm, 195 µm, and 275 µm, respectively. The decrease in ultimate tensile strength is 51 % compared to the base metal’s ultimate tensile strength. Horizontal and vertical microhardness tests show that welding with one sequence produces the greatest microhardness value, but there is a decrease in the microhardness value using welding with two to four sequences. Orbital pipe welding results in different depths of penetration at each pipe position. The largest and smallest depth of penetration was 4.11 mm and 1.60 mm, respectively


Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1602 ◽  
Author(s):  
Yong Hu ◽  
Tong Wu ◽  
Yue Guo ◽  
Wenyang Wang ◽  
Mingkai Song ◽  
...  

SiCp/6061Al composites have been developed and widely applied in many fields, such as automobile, aerospace, shipping, and so on. Considering heat treatment, service environment, and strength of composites, this paper comprehensively studies the mechanical properties of SiCp/6061Al composites with a large range of SiC mass fractions under T6 treatments and different tensile temperatures. SiCp/6061Al composites were successfully prepared by hot press sintering at various SiC mass fractions (0–30%), and the influences of SiC concentration and T6 treatment on the mechanical properties of composites were characterized via tensile tests at room temperature, 100, and 200 °C. Microstructure and fracture surfaces of composites with various SiC concentrations were further analyzed by optical microscope and SEM. The formula for the biggest critical reinforcement concentration for the saturated distribution of SiC is proposed to reveal the strengthening rule of different SiC concentrations. Results show that the effect of T6 treatment on the mechanical properties of composites is a marked increase in tensile strength and an obvious decrease in elongation. The increase in the SiC mass fraction, except at 30%, is able to bring an increase in tensile strength and a decrease in elongation, and the change of the elongation is insignification in T6-treated specimens. The tensile strength of T6-treated specimens decreases as temperature increases, and the composite has a maximum elongation at 100 °C.


2014 ◽  
Vol 529 ◽  
pp. 237-241
Author(s):  
Juan Jia ◽  
Shuang Xin Liu ◽  
Dierk Rabbe

The mechanical properties of the rolled isotactic polypropylene and the morphology of fracture surfaces were measured and observed by tensile tests and the scanning electron microscopy. And then the tensile fracture behaviors along the rolling and transvers directions of the rolled samples were analyzed. After rolling, strong anisotropy mechanical properties occurred along the rolling and transverse directions: high tensile strength with low total elongation along the rolling direction and low tensile strength with high total elongation along the transverse direction. After tensile test, three characteristic structures were found on the fracture surfaces. The tensile fracture behavior of the rolled samples is: stress concentration happens on the edge of tensile sample and then fracture develops to the center part of the tensile sample. When the fracture is big enough, the tensile sample will be failed very quickly.


2017 ◽  
Author(s):  
Zhenglong Liang ◽  
Qi Zhang

A novel process which combines casting with forging during one process was proposed to improve mechanical properties and refine microstructure. The microstructure evolution of as-cast samples and forged samples were analyzed by optical microscope and scanning electron microscope (SEM). The tensile properties and micro-hardness were also measured. The results show that combination of casting and forging can improve microstructure and decrease porosity of casting samples, consequently contributing to a better fatigue performance. The ultimate tensile strength and elongation were increased after forging process, however, the yield strength and micro-hardness decreased.


2012 ◽  
Vol 602-604 ◽  
pp. 623-626 ◽  
Author(s):  
Seon Ho Kim ◽  
Kyu Sik Kim ◽  
Shae K. Kim ◽  
Young Ok Yoon ◽  
Kyu Sang Cho ◽  
...  

In this study, the microstructures and mechanical properties of the recently developed Eco-2024-T3 alloy were examined. Eco-2024 is made using Eco-Mg (Mg-Al2Ca) in place of element Mg during the manufacture of alloy 2024-T3. This is an alloy that has economic advantage and excellent properties. Alloy Eco-2024 showed smaller crystal grains that were distributed more evenly compared to the existing alloy 2024-T3. It consisted of Al matrices containing minute amounts of Al2CuMg, Al2Cu, and Ca phases and showed microstructures with reduced amounts of Fe phases or oxide. As a result of tensile tests, this alloy exhibited yield strength of 413 MPa, tensile strength of 527 MPa, and elongation of 15.4%. In other words, it showed higher strength than the existing alloy 2024 but was similar to the existing alloy 2024 in terms of elongation. In fatigue tests, alloy Eco-2024-T3 recorded fatigue limit of 330 MPa or around 80% of its yield strength; this is a much more excellent property compared to the existing alloy 2024-T3, which has fatigue limit of 250 MPa. Based on the aforementioned results, the correlation between the excellent mechanical properties of alloy Eco-2024-T3 and its microstructure was examined.


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