Dynamic Observation of Hydrogen Gas Release during Crack Propagation in Al-Zn-Mg Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 168-173
Author(s):  
Keitaro Horikawa ◽  
Shunsuke Hokazono ◽  
Hidetoshi Kobayashi
Keyword(s):  
Grain Boundary ◽  
High Speed ◽  
Notch Root ◽  
Sampling Rate ◽  
Testing Machine ◽  
Initial Crack ◽  
Hydrogen Gas ◽  
Gas Evolution ◽  
Tensile Testing Machine ◽  
Air Atmosphere

We have developed a new testing device, which is capable of detecting hydrogen gas evolution from the microstructural changes at the same timing. The device is composed of the tensile testing machine equipped with a high-speed microscope and two types of quadrupole mass spectrometers installed in the ultrahigh vacuum chamber. Sampling rate of microscopic observation is 2000 fps. Hydrogen or deuterium was pre-charged to the 7075 aluminum alloy by means of the slow strain rate deformation, together with the exposure under the humid air atmosphere. The hydrogen amount was measured by using a thermal desorption analysis in advance. As a result, it was revealed that hydrogen gas was evolved when the surface crack was generated around the notch root of the test specimen. SEM observation also showed that the initial crack is related to the propagation of grain boundary fracture around the notch root. When compared to the microstructure and the hydrogen gas evolution near the notch root, the hydrogen amount evolved at the grain boundary was estimated to be about 3.0×10-7mol/m2.

Effect of Coarse-Grained Ring on Mechanical Properties and Cutting Performance of 2011 Aluminum Alloy Extruded Bar

2021 ◽  
Vol 1035 ◽  
pp. 114-118
Author(s):  
Chang Liang Shi ◽  
Yan Ping Niu ◽  
Yi Min Lin ◽  
Quan Hu ◽  
Xin Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Tensile Testing ◽  
High Speed ◽  
Testing Machine ◽  
Eutectic Phase ◽  
Cutting Performance ◽  
Coarse Grained ◽  
Tensile Testing Machine

The effects of coarse-grained ring on the mechanical properties and cutting performance of 2011 aluminum alloy extruded bars were studied by metallographic microscope, scanning electron microscope, tensile testing machine and high-speed lathe. The results show that the microstructure of aluminum alloy extruded bar was composed of α-Al phase, Al7Cu2Fe phase, CuAl2 phase and SnBi eutectic phase. There was a coarse-grained ring in the aluminum alloy extruded bar. The coarse-grained ring reduced the mechanical properties and cutting performance of the aluminum alloy extruded bar. The aluminum alloy extruded bar with a diameter of 30 mm had a coarse-grained ring depth of 9 mm and lower mechanical properties, whose the tensile strength was 287.9 MPa, the elongation was 17%, the cutting performance was poor and the chips were long. The aluminum alloy extruded bar with a diameter of 40 mm had a coarse-grained ring depth of 1 mm, higher mechanical properties and better cutting performance, whose the tensile strength was 394.5 MPa, the elongation was 23.5%, the chips were fine and uniform.

scholarly journals Shock Absorbers Damping Characteristics by Lightweight Drop Hammer Test for Naval Machines

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 772
Author(s):  
Andrzej Grządziela ◽  
Marcin Kluczyk
Keyword(s):  
High Speed ◽  
Response Spectrum ◽  
Dynamic Stiffness ◽  
Testing Machine ◽  
Tensile Testing Machine ◽  
Marine Fuel ◽  
Drop Hammer ◽  
Shock Absorbers ◽  
Technical Requirements ◽  
Initial Objective

The technical requirements for naval ships machine foundations are far more strict in comparison to merchant’s vessels. These requirements are confirmed in the military standardization of many countries. Underwater Explosion (UNDEX phenomena) detonation pulses, force naval engineers to design and implement different shock absorbers made from a wide variety of materials. This study presents the tests results of typical shock absorber designs made of various types of rubber and elastomers. The initial objective of the study was to determine the energy absorption of shock impacts, the choice of materials capable of operating within the temperature range of 0 °C to 70 °C, resistance to contact with oils and marine fuel, performance at frequencies ranging from 5 to 30,000 Hz, and absorption no less than 40% of harmonic vibration energy. Initial studies conducted on tensile testing machine were used to determine the static and dynamic stiffness of a shock absorbers. Considerations of stiffness coefficient for the linear and nonlinear range is typical for shock pulses. Further tests were carried out on a lightweight drop hammer to determine the characteristics of the damping coefficient for high-speed wave interactions—Shock Response Spectrum (SRS). The final aim of the study was to assess the repeatability of the shock absorbers response to multiple impact loads. Mechanical properties describing possibilities of tested dampers materials to absorb energy of UNDEX were also presented.

scholarly journals Construction of Three-Dimensional Crack Calculation Method for Transparent Rock-Like Materials Based on Stereo Vision Principle

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Shu Zhu ◽  
Zhihua Luo ◽  
Zhu Zhende ◽  
Yufeng Gao ◽  
Nan Wu
Keyword(s):  
Calculation Method ◽  
High Speed ◽  
Testing Machine ◽  
Three Dimensional ◽  
Initial Crack ◽  
Surrounding Rock ◽  
Stereoscopic Vision ◽  
Deformation And Failure ◽  
Rock Reinforcement ◽  
Underground Caverns

Disasters of deep underground caverns often occur during excavation or operation stage, which is closely related to the growth and evolution of surrounding rock cracks. The understanding of spatial distribution of internal cracks in rock mass is the key to reveal its deformation and failure mechanism. The transparent resin material with prefabricated crack was used to simulate the initial crack inside the rock, and the uniaxial compression experiment of transparent rock material under complete stress-strain path was carried out by using the rock mechanical rigidity testing machine. Four high-speed cameras were arranged around it to record the images of the same moment from different angles. Based on the theory of stereoscopic vision, a calculation method for the three-dimensional constitutive structure of crack propagation inside the rock was proposed, which can quantitatively describe the crack spatial morphological change. Therefore, the calculation method provides a reliable theoretical support for the surrounding rock reinforcement of underground engineering.

scholarly journals Erratum to: New tension mechanism for high-speed tensile testing machine

2017 ◽  
Vol 18 (3) ◽  
pp. 561-561
Author(s):  
B. Ruan ◽  
G. Q. Li ◽  
Y. Chen ◽  
P. Mitrouchev ◽  
B. He ◽  
...  
Keyword(s):  
Tensile Testing ◽  
High Speed ◽  
Testing Machine ◽  
Tensile Testing Machine

scholarly journals Synthetic Environmentally Friendly Castor Oil Based-Polyurethane with Carbon Black as a Microphase Separation Promoter

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1333 ◽  
Author(s):  
Jia-Wun Li ◽  
Wen-Chin Tsen ◽  
Chi-Hui Tsou ◽  
Maw-Cherng Suen ◽  
Chih-Wei Chiu
Keyword(s):  
Carbon Black ◽  
Castor Oil ◽  
High Speed ◽  
Microphase Separation ◽  
Soft Segment ◽  
Testing Machine ◽  
Environmentally Friendly ◽  
Mechanical Analysis ◽  
Tensile Testing Machine ◽  
Naoh Solution

This study created water polyurethane (WPU) prepolymer by using isophorone diisocyanate, castor oil, dimethylolpropionic acid, and triethanolamine (TEA) as the hard segment, soft segment, hydrophilic group, and neutralizer, respectively. TEA, deionized water, and carbon black (CB) were added to the prepolymer under high-speed rotation to create an environmentally friendly vegetable-oil-based polyurethane. CB served as the fortifier and promoter of microphase separation. Fourier transform infrared spectroscopy was performed to elucidate the role of H-bond interactions within the CB/WPUs. Additionally, atomic force microscopy was conducted to determine the influence of H-bond interactions on the degree of microphase separation in the WPU. Furthermore, this study used four-point probe observation to discover the materials’ conductivity of CB in the WPU. Thermogravimetric analysis and dynamic mechanical analysis were performed to measure the thermal properties of the CB/WPUs. The mechanical properties of CB/WPUs were measured using a tensile testing machine. The CB/WPUs were also soaked in 1 wt.% NaOH solution for different amounts of time to determine the degradation properties of the CB/WPUs. Finally, scanning electron microscopy was performed to observe the topography of the CB/WPUs after degradation.

Dynamic Tensile Characteristics of DP600 Steel Sheets for Automotive Applications

2012 ◽  
Vol 509 ◽  
pp. 40-45
Author(s):  
Dan Yang Dong ◽  
Yang Liu ◽  
Lei Wang ◽  
Chang Sheng Liu
Keyword(s):  
Strain Rate ◽  
Tensile Testing ◽  
High Speed ◽  
Greenhouse Gas Emission ◽  
Testing Machine ◽  
Fracture Mechanisms ◽  
Strain Rates ◽  
Automotive Applications ◽  
Tensile Testing Machine ◽  
Steel Sheets

To reduce fuel consumption and greenhouse gas emission, dual phase (DP) steels have been considered for automotive applications due to their higher tensile strength, better initial work hardening along with larger elongation compared to conventional grade of steels. In such applications, which would create potential safety and reliability issues under dynamic loading, the mechanical behavior of DP steel considering the strain rate must be examined. In the present study, the dynamic tensile behavior of DP600 steel sheets was investigated using a high-speed tensile testing machine at various strain rates. And the quasi-static tensile testing was also conducted on the steel to understand the effect of the strain rate on the tensile property. The fracture mechanisms of the steel were also analyzed. The results show that the mechanical properties of DP600 steel are noticeably influenced by the strain rates. As the strain rate increases, the strength of the steel increases and the obvious yield phenomenon can be observed when the strain rate is above 0.01 s-1. The fracture elongation of DP600 steels decreases with increasing strain rate from 0.001 to 1 s-1, then increases up to the strain rate of 100 s-1 and reaches the lowest value at the strain rate of 1000 s-1. DP600 steel sheet exhibit typical ductile fracture characteristics with dimples morphology of the facture surface when tensile deformed at various strain rates.

Study on Organization and Properties of the New Wear-Resistant Steel

2011 ◽  
Vol 704-705 ◽  
pp. 1423-1428 ◽  
Author(s):  
Ning Bo Li ◽  
Jing Pei Xie ◽  
Wen Yan Wang
Keyword(s):  
High Speed ◽  
Lath Martensite ◽  
Testing Machine ◽  
Residual Austenite ◽  
Wear Testing ◽  
Treatment Technique ◽  
Resistant Steel ◽  
Tensile Testing Machine ◽  
Wear Resistant ◽  
The Impact

By means of wear analysis of the wear-resistant steel used in the process, and adjust the wear-resistant steel composition, by adding alloying elements Cr, Mo and so on, optinlizing heat treatment technique, to get new wear-resistant steel. The HR-150A rock well hardness tester and JB-300B impact tester as well as SHIMADZUAG-I250KV on electronic tensile testing machine were used to test the mechanical properties of materials. In the test of friction and wear performance was done using the high temperature and high-speed friction of wear-testing maching (MMS-1G), and analysis of microscopy and the wear morphology by JSM-5610LV SEM．The results showed that: The hardness of new wear-resistant steel reaches HRC53, the impact toughness 23J/cm2, And at this moment, the sample matrix is the microstructure of small lath martensite and residual austenite.

scholarly journals Analysis of the Acid and Alkali Resistance of Superhydrophobic Paper Mulch

2021 ◽  
Author(s):  
Fangyuan Zhang ◽  
Anling Li ◽  
Wuyun Zhao
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
High Speed ◽  
Mass Loss Rate ◽  
Testing Machine ◽  
Alkali Resistance ◽  
Tensile Testing Machine ◽  
Alkaline Environment ◽  
Microscopic Morphology ◽  
Superhydrophobic Paper

Abstract The paper mulch will inevitably suffer the influence of the acidic or alkaline environment during the usage. To evaluate the influence of the acidic or alkaline environment on the corrosion resistance of the paper film, we investigate the method of immersing the paper film with acid and alkali solution. We use the hydrophobic SiO2 to prepare a superhydrophobic paper mulch with a contact angle of 155° with water. Two kinds of superhydrophobic paper mulch were put into H2SO4 solution with pH 4.6 and NaOH solution with pH 8.5, respectively. After soaking for 48h, we use a contact angle tester, a tensile testing machine, and a high-speed camera to compare the contact angle, mechanical properties, and bounce performance of these two paper mulches. The results showed that the tensile strength and droplet bounce height of the superhydrophobic paper mulch decreased after being soaked in the acid or alkaline solution for 48 hours. The mass-loss rate of the paper mulch in acid solution is more significant, and its contact angle is still greater than 145° which treats as a good bounce performance. The microscopic morphology of the paper showed that SiO2 can form a superhydrophobic structure on the surface of the paper mulch. The method is simple and environmentally friendly and can solve the problem of poor acid and alkali corrosion resistance of the paper mulch. It has extraordinary significance in reducing the environmental pollution.

Evaluation of the Failure Elongation of Steel Sheets for an Auto-Body at the Intermediate Strain Rate

2008 ◽  
Vol 385-387 ◽  
pp. 749-752 ◽  
Author(s):  
Seok Bong Kim ◽  
Hoon Huh
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Tensile Elongation ◽  
Testing Machine ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Result ◽  
Tensile Testing Machine ◽  
Static State ◽  
Steel Sheets

This paper deals with the dynamic failure elongation of mild steel, SGACD and advanced high strength steel sheets such as TRIP600, DP600 and TWIP steels. The failure elongation has been obtained from the high speed tensile testing machine with various strain rates ranged from 0.003/s to 200/s. The experimental result demonstrates that the tensile elongation does not simply decrease as the strain rate increases, but it decreases from the quasi-static state to the strain rate of 0.1 or 1/s and increases again up to the strain rate of 100/s. Furthermore, some high strength steels have the tendency that the tensile elongation increases as the strain rate increases. Moreover, the localized strain rate hardening in the necking region induces the increase of elongation.

Effect of Strain Rate on Hydrogen Evolution during Deformation in Al-Zn-Mg Alloys

2012 ◽  
Vol 706-709 ◽  
pp. 295-300
Author(s):  
Keitaro Horikawa ◽  
Hiroyuki Yamada ◽  
Masahide Mutsuo ◽  
Hidetoshi Kobayashi
Keyword(s):  
Strain Rate ◽  
Grain Boundaries ◽  
Testing Machine ◽  
Hydrogen Gas ◽  
Mg Alloys ◽  
Second Phase ◽  
Gas Evolution ◽  
Hydrogen Atoms ◽  
Deformation And Fracture ◽  
The Moment

Hydrogen gas evolution behaviour during deformation and fracture in Al-Zn-Mg alloys with and without copper additions was examined by using a testing machine equipped with a quadrupole mass spectrometer in an ultrahigh vacuum chamber (QMS-UHV) and by a hydrogen microprint technique (HMT). The QMS-UHV testing revealed that hydrogen gas was evolved at the moment of grain boundary fracture, in particular. This suggested that hydrogen atoms primarily dissolved were trapped at the grain boundaries before the fracture. It was also revealed that hydrogen gas evolution behaviour was changed according to the testing strain rate. The HMT also revealed that silver particles, which represented the emission sites of hydrogen, were observed mainly around the second phase inclusions and the grain boundaries.

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