scholarly journals Effect of a New Grain Refiner (Al–Ti–Mg–Ce) on Hardness, Tensile, and Impact Properties of Al–7Si Alloy

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 228 ◽  
Author(s):  
Jitao Zhao ◽  
Mingfang Shi ◽  
Zhenqing Wang ◽  
Lidan Xu
Keyword(s):  
Impact Toughness ◽  
Strain Rate ◽  
Tensile Properties ◽  
Rate Sensitivity ◽  
Mechanical Tests ◽  
Hopkinson Pressure Bar ◽  
Grain Refiner ◽  
Impact Properties ◽  
Impact Performance ◽  
The Impact

Through studying the effects of the Al–5Ti-x(Mg–30%Ce) refiner on the microstructure of the Al–7Si alloy, we investigated the hardness, tensile, and impact properties of the Al–Si alloy before and after refinement. The refinement results show that Mg–30%Ce can improve the refinement effect of Al–5Ti on Al–7Si, and also refine α-Al and eutectic Si in Al–7Si. When 2%Mg–30%Ce is added, the refining effect of the aluminum–silicon alloy is most obvious. After refinement, the hardness and tensile properties of the Al–7Si alloy improve. When 2%Mg–30%Ce is added to the refiner, the tensile properties of the Al–Si alloy are the best. Dynamic mechanical tests were conducted on refined Al–7Si alloy. The impact toughness of Al–7Si–(Al–5Ti-2(Mg–30%Ce) improved and the impact toughness reached 34.91 J/cm2, which is 78.7% higher than that of Al–7Si–(Al–5Ti) specimens. The separate Hopkinson pressure bar test results show that, under a high strain rate, the strain rate sensitivity of the prepared Al–Si alloy is significant. The specimens of Al–7Si–(Al–5Ti-2(Mg–30%Ce) demonstrated the best anti-impact performance at the same velocity.

High Strain Rate Compressive Behaviour of Selective Laser Melted Ti-6Al-4V

2017 ◽  
Vol 890 ◽  
pp. 323-326 ◽  
Author(s):  
Maziar Ramezani ◽  
Emmanuel Flores-Johnson ◽  
Lu Ming Shen ◽  
Thomas Neitzert
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Shear Failure ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Rate Sensitivity ◽  
Melting Process ◽  
Mechanical Tests ◽  
Hopkinson Pressure Bar

Ti-6Al-4V alloy is one of the most important engineering alloys, combining attractive properties with inherent workability. The aim of this study is to investigate the effect of strain rate on the compressive mechanical properties of Ti6Al4V alloy manufactured by a selective laser melting process. The mechanical tests were performed by means of a compression split Hopkinson pressure bar apparatus under high strain rate ranging from 1400 s-1 to 4500 s-1. The true stress-strain curves obtained from static and dynamic compressive tests show strain rate sensitivity from quasi-static (peak strength 1300MPa) to high strain rate (peak 1500 MPa). Within the high strain rate range tested, the strain rate sensitivity is not remarkable. The fractographic analysis shows a relatively smooth and smeared fractured surface along with a dimple like structure. The observation of elongated dimples confirms the operation of a dynamic shear failure mechanism for the additively manufactured Ti-6Al-4V parts.

Research on the Dynamic Characteristics of a Sphere Material

2012 ◽  
Vol 246-247 ◽  
pp. 482-486
Author(s):  
Yong Cheng Wang
Keyword(s):  
Dynamic Characteristics ◽  
Split Hopkinson Pressure Bar ◽  
Polymer Materials ◽  
Butadiene Rubber ◽  
Hopkinson Pressure Bar ◽  
Impact Properties ◽  
Impact Performance ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
The Impact

In this paper, we make a research on the dynamic characteristics of a sphere material, mainly using golf as an example. Golf is composed of such as poly butadiene rubber or other synthetic rubber, ion resin, etc. and different viscoelastic materials. The viscoelastic characteristics of this material are selected as spectrometer for evaluation. However, the impact performance of the golf course materials cannot pass such a test to assess, because golf have great impact on the deformation and high strain rate viscoelastic spectrometer. On the other hand, the impact properties of the metal can be used to assess the split Hopkinson pressure bar. However, the rod is not suitable to be used to evaluate the strain wave interference and noise propagation in the impact properties of the polymer materials. Therefore, the split Hopkinson pressure bar has been modified to make it more applicable to the valuation of the polymer materials. The article is based on the concept of modified split Hopkinson pressure bar to make the golf impact evaluation of the performance materials.

Effects of prestrain on high temperature impact properties of 304L stainless steel

2010 ◽  
Vol 25 (4) ◽  
pp. 754-763 ◽  
Author(s):  
Woei-Shyan Lee ◽  
Chi-Feng Lin ◽  
Tao-Hsing Chen ◽  
Meng-Chieh Yang
Keyword(s):  
Stainless Steel ◽  
Flow Stress ◽  
Strain Rate ◽  
Work Hardening ◽  
Rate Sensitivity ◽  
304L Stainless Steel ◽  
Impact Properties ◽  
Work Hardening Rate ◽  
The Impact ◽  
Sensitivity Increase

The effects of prestrain, strain rate, and temperature on the impact properties of 304L stainless steel are investigated using a compressive split-Hopkinson pressure bar. The impact tests are performed at strain rates ranging from 2000 to 6000 s−1 and temperatures of 300, 500, and 800 °C using 304L specimens with prestrains of 0.15 or 0.5. The results show that the flow stress, work-hardening rate, and strain rate sensitivity increase with increasing strain rate or decreasing temperature. As the prestrain increases, the flow stress and strain rate sensitivity increase, but the work-hardening rate decreases. The temperature sensitivity increases with an increasing strain rate, temperature, and prestrain. Overall, the effects of prestrain on the impact properties of the tested specimens dominate those of the strain rate or temperature, respectively. Finally, optical microscopy observations reveal that the specimens fracture primarily as the result of the formation of adiabatic shear bands.

scholarly journals Study on the dynamic properties of AM-SLM AlSi10Mg alloy using the Split Hopkinson Pressure Bar (SHPB) technique

2018 ◽  
Vol 183 ◽  
pp. 04005 ◽  
Author(s):  
Bar Nurel ◽  
Moshe Nahmany ◽  
Adin Stern ◽  
Nahum Frage ◽  
Oren Sadot
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Static Mechanical ◽  
Split Hopkinson ◽  
Pressure Bar

Additive manufacturing by Selective Laser Melting of metals is attracting substantial attention, due to its advantages, such as short-time production of customized structures. This technique is useful for building complex components using a metallic pre-alloyed powder. One of the most used materials in AMSLM is AlSi10Mg powder. Additively manufactured AlSi10Mg may be used as a structural material and it static mechanical properties were widely investigated. Properties in the strain rates of 5×102–1.6×103 s-1 and at higher strain rates of 5×103 –105 s-1 have been also reported. The aim of this study is investigation of dynamic properties in the 7×102–8×103 s-1 strain rate range, using the split Hopkinson pressure bar technique. It was found that the dynamic properties at strain-rates of 1×103–3×103 s-1 depend on a build direction and affected by heat treatment. At higher and lower strain-rates the effect of build direction is limited. The anisotropic nature of the material was determined by the ellipticity of samples after the SHPB test. No strain rate sensitivity was observed.

scholarly journals The Microstructure and Property of the Heat Affected zone in C-Mn Steel Treated by Rare Earth

2019 ◽  
Vol 38 (2019) ◽  
pp. 362-369 ◽  
Author(s):  
Ming-ming Song ◽  
Yu-min Xie ◽  
Bo Song ◽  
Zheng-liang Xue ◽  
Nan Nie ◽  
...  
Keyword(s):  
Rare Earth ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
Acicular Ferrite ◽  
Steel Matrix ◽  
Impact Properties ◽  
Treated Steel ◽  
The Impact ◽  
Welding Processes ◽  
Mn Steel

AbstractThe microstructures and impact properties of the heat affected zone (HAZ) in steel treated by rare earth (RE) under different welding processes were discussed. The effect of Al on the impact properties of the HAZ in RE treated steel was analyzed. It finds that when the welding t8/5 is smaller than 111 s, the main microstructure in steels is bainite/widmanstatten. The impact toughness of the HAZ is lower than that of the steel matrix. When t8/5 is more than 250 s, the microstructure is mainly acicular ferrite (AF) in the steel treated by RE, and the impact toughness of HAZ is obviously improved. Even under the welding processing with t8/5 about 600 s in RE treated steel can still obtain a lot of AF. While in the steel killed by Al and treated by RE, the main microstructure is parallel cluster of bainite/widmanstatten, and the impact toughness of HAZ is significantly lower than that of low-Al RE treated steel. Al can deteriorate the optimizing of RE treatment on HAZ.

scholarly journals Dynamic Characteristics of Deep Dolomite Under One-Dimensional Static and Dynamic Loads

2019 ◽  
Vol 101 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Jianguo Wang ◽  
Yang Liu ◽  
Kegang Li
Keyword(s):  
Strain Rate ◽  
Axial Compression ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Strength ◽  
Strong Positive Correlation ◽  
Hopkinson Pressure Bar ◽  
Irreversible Damage ◽  
One Dimensional ◽  
Rock Structure ◽  
The Impact

AbstractThe failure characteristics of rock subjected to impact disturbance under one-dimensional static axial compression are helpful for studying the problems of pillar instability and rock burst in deep, high geostress surrounding rock under blasting disturbances. Improved split Hopkinson pressure bar equipment was used for one-dimensional dynamic–static combined impact tests of deep-seated dolomite specimens under axial compression levels of 0, 12, 24, and 36 MPa. The experimental results demonstrate that the dolomite specimens exhibit strong brittleness. The dynamic strength always maintains a strong positive correlation with the strain rate when the axial compression is fixed; when the strain rate is close, the dynamic elasticity modulus and peak strength of the specimens first increase and then decrease with the increase in axial compression, and the peak value appears at 24 MPa. The impact resistance of specimens can be enhanced when the axial compression is 12 or 24 MPa, but when it increases to 36 MPa, the damage inside the specimen begins to cause damage to the dynamic rock strength. Prior to the rock macroscopic failure, the axial static load changes the rock structure state, and it can store strain energy or cause irreversible damage.

scholarly journals Dynamic Mechanical Compression Impulse of Lithium-Ion Pouch Cells

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2105 ◽  
Author(s):  
Alon Ratner ◽  
Richard Beaumont ◽  
Iain Masters
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Lithium Ion ◽  
Rate Sensitivity ◽  
Dynamic Mechanical Properties ◽  
Impact Testing ◽  
Significant Feature ◽  
Dynamic Mechanical ◽  
The Impact

Strain rate sensitivity has been widely recognized as a significant feature of the dynamic mechanical properties of lithium-ion cells, which are important for their accurate representation in automotive crash simulations. This research sought to improve the precision with which dynamic mechanical properties can be determined from drop tower impact testing through the use of a diaphragm to minimize transient shock loads and to constrain off-axis motion of the indenter, specialized impact absorbers to reduce noise, and observation of displacement with a high speed camera. Inert pouch cells showed strain rate sensitivity in an increased stiffness during impact tests that was consistent with the poromechanical interaction of the porous structure of the jellyroll with the liquid electrolyte. The impact behaviour of the inert pouch cells was similar to that of an Expanded Polypropylene foam (EPP), with the exception that the inert pouch cells did not show hysteretic recovery under the weight of the indenter. This suggests that the dynamic mechanical behaviour of the inert pouch cells is analogous to a highly damped foam.

Plastic deformation and fracture characteristics of Hadfield steel subjected to high-velocity impact loading

2002 ◽  
Vol 216 (10) ◽  
pp. 971-982 ◽  
Author(s):  
W-S Lee ◽  
T-H Chen
Keyword(s):  
Strain Rate ◽  
Work Hardening ◽  
Shear Bands ◽  
Rate Sensitivity ◽  
Constitutive Law ◽  
Hadfield Steel ◽  
Flow Strength ◽  
Rate Dependent ◽  
Work Hardening Rate ◽  
The Impact

Investigation of the impact behaviour of Hadfield steel has been carried out in a broad range of strain rates from 10−3 to 9 × 103s−1 by means of a servo-hydraulic machine and a compressive split Hopkinson bar. The effects of strain rate on the impact properties, substructure evolution and fracture resistance have been evaluated. The observed stress-strain response is influenced greatly by strain rate, resulting in obvious changes of work hardening rate, strain rate sensitivity and activation volume. This rate-dependent behaviour is in good agreement with model predictions using the Zerilli-Armstrong constitutive law. Dislocation tangle and deformation twin substructures are also found to develop as a function of strain rate. Increasing dislocation and twin densities enhance the work hardening rate and flow strength. Catastrophic failure at high rates results from the formation of localized shear bands. With increasing strain rate, there is an increase in brittle cleavage microfracture, resulting in ductility loss. Microcracking initiates at grain boundaries due to the presence of carbide precipitates.

The Effect of Pre-Strain and Strain Aging on Properties of X100 Line Pipe

2013 ◽  
Vol 690-693 ◽  
pp. 2270-2274
Author(s):  
Qiu Rong Ma ◽  
Hong Da Chen ◽  
Yan Hua Li ◽  
He Li
Keyword(s):  
Tensile Strength ◽  
Impact Toughness ◽  
Yield Strength ◽  
Tensile Properties ◽  
Aging Temperature ◽  
Strain Aging ◽  
Longitudinal Direction ◽  
Line Pipe ◽  
Toughness Test ◽  
The Impact

Tensile and impact toughness test on X100 line pipe with different pre-strain at different aging temperature were conducted to study the effect of pre-strain and aging temperature on properties of X100 line pipe. The result shows that yield strength and tensile strength of X100 line pipe would increase significantly with the introduction of pre-strain, while the impact toughness would decrease significantly. Effect of strain aging on tensile properties of X100 line pipe are more significantly. The yield strength, and tensile strength would increase significantly with the introduction of strain aging both transversal and longitudinal direction.

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