Tensile Properties and Fracture Behavior of Aluminum Alloy Foam Fabricated from Die Castings without Using Blowing Agent by Friction Stir Processing Route
21
Citation
40
Reference
10
Related Paper
Citation Trend
Abstract:
Al foam has been used in a wide range of applications owing to its light weight, high energy absorption and high sound insulation. One of the promising processes for fabricating Al foam involves the use of a foamable precursor. In this study, ADC12 Al foams with porosities of 67%-78% were fabricated from Al alloy die castings without using a blowing agent by the friction stir processing route. The pore structure and tensile properties of the ADC12 foams were investigated and compared with those of commercially available ALPORAS. From X-ray computed tomography (X-ray CT) observations of the pore structure of ADC12 foams, it was found that they have smaller pores with a narrower distribution than those in ALPORAS. Tensile tests on the ADC12 foams indicated that as their porosity increased, the tensile strength and tensile strain decreased, with strong relation between the porosity, tensile strength, and tensile strain. ADC12 foams exhibited brittle fracture, whereas ALPORAS exhibited ductile fracture, which is due to the nature of the Al alloy used as the base material of the foams. By image-based finite element (FE) analysis using X-ray CT images corresponding to the tensile tests on ADC12 foams, it was shown that the fracture path of ADC12 foams observed in tensile tests and the regions of high stress obtained from FE analysis correspond to each other. Therefore, it is considered that the fracture behavior of ADC12 foams in relation to their pore structure distribution can be investigated by image-based FE analysis.Keywords:
Brittleness
Blowing agent
Tensile testing
Small Punch Test(SPT) with miniature specimen is a new technique applied to non-destructive evaluation of material mechanical properties.SPT was performed for dozens of materials to investigate the relationship between the axial deflection δ of SPT specimen and the elongation A of the fractured specimen subjected to tensile testing.Experimental results show that there is not a linear relation between δ and A for tested dozens of materials.But according to the ultimate tensile strength and yield-strength ratio,above-mentioned materials can be divided into different groups.Then the axial deflection δ of SPT can be linearly correlated to the A of the fractured specimen subjected to tensile testing in each group respectively.For materials,whose ultimate tensile strength is less than 600MPa,two groups can be devided according to the yield-strength ratio 0.67.A linear empirical correlation formula was proposed for each of group.No obvious correlation was found for materials whose ultimate tensile strength is larger than 600MPa,due to data insufficiency.
Tensile testing
Elongation
Cite
Citations (0)
117205 Variations of Porosity and Pore Structure of ADC12 Porous Aluminum by Amount of Blowing Agent
Porous aluminum is expected to be applied as a multifunctional material in automobiles because of very lightweight, high specific strength and high energy absorptivity. When aluminum alloy die castings are used as a starting material in the fabrication of porous aluminum, the gases intrinsically contained in the die casting can be used to generate pores. From the fact, it can be expected that porous aluminum with high porosity can be fabricated by adding a small amount of blowing agent. In this study, the amount of blowing agent from 0 to 1.4 mass% is added to ADC12 aluminum alloy die castings containing three different amounts of gases and porous aluminum is fabricated by the FSP (friction stir processing) route precursor method. The variations of porosity and pore structure with the amount of added blowing agent are investigated. Through the experimental results, it is shown that, by using a blowing agent of approximately 0.6 mass%, ADC12 porous aluminum can be fabricated with high porosity and good pore structure.
Blowing agent
Die casting
Alonizing
Cite
Citations (0)
A new in-soil tensile test apparatus was developed to simulate the in-soil stress condition of geosynthetics in a real working state. An in-soil tensile test with or without friction was conducted, along with in-air tensile tests of eight types of geosynthetics, to evaluate tensile properties, including tensile load and secant tensile stiffness under different confining stresses using various methods. Under confinement, the tensile properties of geosynthetics increased with growing confinement, which were greater than those for the in-air tensile test, and the tensile properties were similar for tests with or without friction. The tensile load improvement factors FT−σ and fT−σ were introduced to quantify the confinement and reinforcement–soil friction differences between different tests, and the improvement ratios γ1 and γ2 were proposed to quantify the improvement of tensile load under confinement for the test with and without friction, respectively. Two formulas were proposed to predict the confined tensile properties of geosynthetics. The results showed that confinement was the major factor that improved the tensile properties of geosynthetics compared to reinforcement–soil friction. When the improvement ratio is not less than 1.5, the confined tensile load should replace the in-air tensile load with the tensile strength design of geosynthetics, which provides an insight into the design of reinforced soil structures.
Geosynthetics
Tensile testing
Cite
Citations (2)
본 연구에서는 시멘트 고결토 내에 실린더를 내장시킨 다음 유압으로 공시체 내부에서 인장력을 가하여 공시체를 직접 파괴시키는 직접인장시험 방법에 대한 연구를 수행하였다. 또한 기존 아령모양의 공시체를 이용한 직접인장시험과 대표적인 간접인장시험인 쪼갬인장시험을 실시하여 인장시험 방법에 따른 차이를 비교하였다. 인장시험용 공시체는 모래/시멘트비를 3:1 또는 1:1로 제작한 다음 7일 및 28일 동안 대기중 양생하였으며, 동일한 경우에 대해 10개의 공시체를 실험하여 평균값을 비교하였다. 한편 일축압축시험도 실시하여 일축압축강도와 인장강도의 비를 분석하였다. 내장형 실린더를 이용한 직접인장시험으로부터 얻은 인장강도는 아령모양 공시체를 이용한 직접인장시험으로부터 얻은 값보다 다소 높은 인장강도를 보였지만, 아령모양 공시체를 이용한 시험방법은 공시체 제작이 불편하고 시험 중 변곡부에서 파괴되는 경우가 자주 발생하였다. 탄성파괴를 일으키는 콘크리트나 암석에 적용하는 쪼갬인장시험방법으로 부터 얻은 인장강도는 표준편차가 가장 컸을 뿐 아니라, 시멘트 고결토와 같이 강도가 상대적으로 약해 탄소성파괴를 일으키는 재료에는 적용하기 어려웠다. In this study, a cylinder embedded within cemented soils was used to cause directly tensile failure of cemented soils. An existing dumbbell type direct tensile test and a split tensile test that is most general indirect tensile test were also carried out to verify the developed built-in cylinder tensile test. Testing specimens with two different sand/cement ratios (1:1 and 3:1) and two curing periods (7 and 28 days) were prepared and tested. Total 10 specimens were prepared for each case and their average value was evaluated. Unconfined compression tests were also carried out and the ratio of compressive strength and tensile strength was evaluated. The tensile strength determined by built-in cylinder tensile test was slightly higher than that by dumbbell type direct tensile test. The dumbbell type test has often failed in joint part of specimen and showed some difficulty to prepare a specimen. Among three tensile testing methods, the standard deviation of tensile strength by split tensile test was highest. It was shown that the split tensile test is applicable to concrete or rock with elastic failure but not for cemented soils having lower strength.
Tensile testing
Cite
Citations (3)
Currently the development trend of composite materials shifts to the reuse of natural fiber (back to nature) as a substitute for synthetic fibers. Measurement of the mechanical properties of fiber (reinforcement) plays an important role in quality control. One of the most important mechanical properties of fiber is its tensile strength. Tensile strength of fiber can be known through tensile test (tensile test). To do tensile test (tensile test) fiber required tensile test machine (tensile test machine). The tensile test equipment used today is a foreign-made commercial tensile test device imported at an exorbitant price. These conditions cause obstacles in the development of basic industries and natural fiber technology. Most laboratories in higher education institutions and other technology research institutions do not have tensile test equipment support. The purpose of this research is to design a natural fiber tensile test apparats which is cheap and easy to operate. The research method using design tool design (design and manufacture). The result of this research is prototype of natural fiber tensile test which has been successfully tested with technical data: 5N loading capacity, calibration curve accuracy: N = 1.052 V and loading rate 0.014 N/s. The result of tensile test to one natural fiber that used abaca fiber obtained the value of tensile strength of an average of 579,90 MPa. The result of tensile test obtained is comparable with the data of tensile test results in existing literatures then there is conformity with the value of tensile strenght. The results of this study are expected to provide benefits for researchers, academics and industry in supporting the development of national natural fiber industry to increase the competitiveness of industries at the international level.
Tensile testing
Cite
Citations (0)
Using MTS815 Flex Text GT rock mechanics test system,PCI-Ⅱ acoustic emission(AE) test system and SMZ1000 stereomicroscope system and CCD real-time camera system,comprehensive studies are carried out through indirect tensile test and direct tensile test on tensile mechanical properties of beddod salt rock.Through the research,the tensile displacement and tress full process curves of different tensile modes,the tensile strength relationship between the indirect tensile test and the direct tensile test and the relationship between the tensile strength and the uniaxial compressive strength are obtained.The studies show that the direct tensile strength is less than the indirect tensile strength,and the direct tensile test result more truly reflects the characteristics of the tensile strength of salt rock.So it is recommended as much as possible to use the direct tensile test method to test the tensile strength of bedded salt rock.The AE test reveals spatial distribution of AE of different tensile failure modes,and the characters of AE spatial distribution reveals the corresponding force status and damage evolution rule leading failure.The rock failure surface morphology of different tensile test methods shows that the rock failure mode of the indirect tensile test is mainly transgranular fracture,but that of the direct tensile test is mainly intergranular fracture.The failure mode differences are main reasons leading to the strength difference of different tensile test methods.
Tensile testing
Cite
Citations (13)
Brittleness
Atmospheric temperature range
Cite
Citations (25)
Tensile testing
Uniaxial tension
Tension (geology)
Cite
Citations (9)
Abstract Tensile strength of brittle materials is usually obtained through Brazilian tests. It is accepted that failure is initiated at the centre of the sample and that it propagates through the material, creating a tensile failure plane along the vertical diameter or at the majority of it. Then, the tensile stress developed at the centre of the disc is considered as the tensile strength of the material tested. However, the stress state along the vertical diameter is always biaxial, even in the centre of the sample. This implies that the strength measured using such technique is not the uniaxial tensile strength. In this article, the expressions of the stress state supported by a tubular sample subjected to a novel device to determine the tensile strength of brittle materials are described. Besides, it is noticed that the failure plane contains points with the maximum uniaxial tensile strengths so the testing method is adequate to determine the uniaxial tensile strength of brittle materials.
Brittleness
Uniaxial tension
Tensile testing
Cite
Citations (1)
Abstract This paper presents how to determine some mechanical properties of wires subjected to tensile testing. Additional equipment was added to an existing tensile testing machine for wires at high temperatures. A tensile testing procedure for wires at high temperature is described. Tensile tests of Inconel 600 wire were conducted at 700, 800 and 900 °C. The ultimate strength, the yield strength and the percentage elongation after fracture are determined. Analysis of the gathered results is done.
Inconel
Tensile testing
Elongation
Universal testing machine
Cite
Citations (7)