Mechanical Behavior After Stress Relaxation in PVDF

2018 ◽  
Author(s):  
Rafael Luis Menezes Freitas ◽  
Celio Costa ◽  
Erica Gervasoni Chaves ◽  
Sylvia Teixeira
Keyword(s):  
Stress Relaxation ◽  
Tensile Properties ◽  
Room Temperature ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Yield Strain ◽  
Cooling Temperature ◽  
Cooling Conditions ◽  
C 23 ◽  
Processing Stress

This study presents the mechanical properties evaluation of two commercial grades of PVDFs, which were extruded with the same parameters but with different cooling temperatures. After processing, stress relaxation with 7% strain was imposed and tensile properties were measured. The cooling temperature after extrusion were 4°C, 23°C and 80°C. Then, the PVDFs were submitted to stress relaxation at 23°C and 7% strain. The as processed and after relaxation samples were characterized by FTIR, XRD, DSC and tensile tests at 23°C. The stress relaxation at 23 °C resulted in no change in volume fraction of crystallinity for PVDF A and B. The XRD and FTIR, for both PVDFs, showed that the crystalline phases were the same, for all cooling conditions and did not change after the stress relaxation. The tensile properties at room temperature showed that the yield stress was a little affect by the cooling temperature, while Young’s Modulus and yield strain were insensible to the cooling temperature. After the stress relaxation, these three tensile properties were slightly affected for both grades.

Effect of α2 Precipitation on Creep and Tensile Properties of Ga-Added Near-α Titanium Alloys

2018 ◽  
Vol 941 ◽  
pp. 747-752 ◽  
Author(s):  
Tomonori Kitashima ◽  
Masuo Hagiwara ◽  
Tsutomu Ito ◽  
Masao Hayakawa ◽  
Satoshi Iwasaki
Keyword(s):  
Tensile Properties ◽  
Creep Strain ◽  
Room Temperature ◽  
Volume Fraction ◽  
Tensile Elongation ◽  
Lamellar Microstructure ◽  
Tensile Tests ◽  
Strain Rates ◽  
Bimodal Microstructure ◽  
Creep Tests

The effect of α2precipitation on the creep and tensile properties was investigated for bimodal and lamellar microstructures in two Ga-added near-α Ti alloys with Al equivalences of 10.6 and 11.5. Fine α2phase formed in the α phase of both alloys. The volume fraction of the α2phase for the Al equivalences of 10.6 and 11.5 is equivalent to 57.6 % and 73.3 %, respectively, in the binary Ti-Al system at 600 °C. Creep tests were carried out under a constant stress of 310 MPa at 600 °C and tensile tests were performed at room temperature. Lamellar microstructure showed lower minimum creep strain rates than bimodal microstructure for both alloys. The increase in Al equivalence increased creep life by a factor of 1.6 and decreased the minimum creep strain rate from 6.51 × 10-8s-1to 3.99 × 10-8s-1in bimodal microstructure. In addition, the increase in Al equivalence decreased room temperature tensile elongation although both alloys contained a similar volume fraction of equiaxed α in a bimodal microstructure.

Spark Plasma Sintering of Ti-4.5Al-3V-2Fe-2Mo (SP-700)

2010 ◽  
Vol 654-656 ◽  
pp. 819-822
Author(s):  
Genki Kikuchi ◽  
Hiroshi Izui ◽  
Yuya Takahashi ◽  
Shota Fujino
Keyword(s):  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Volume Fraction ◽  
Titanium Boride ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Tib2 Particles

In this study, we focused on the sintering performance of Ti-4.5Al-3V-2Mo-2Fe (SP-700) and mechanical properties of SP-700 reinforced with titanium boride (TiB/SP-700) fabricated by spark plasma sintering (SPS). TiB whiskers formed in titanium by a solid-state reaction of titanium and TiB2 particles were analyzed with scanning electron microscopy and X-ray diffraction. The TiB/SP-700 was sintered at temperatures of 1073, 1173, and 1273 K and a pressure of 70 MPa for 10, 30, and 50 min. The volume fraction of TiB ranged from 1.7 vol.% to 19.9 vol.%. Tensile tests of TiB/SP-700 were conducted at room temperature, and the effect of TiB volume fraction on the tensile properties was investigated.

Influence of Isothermal Forging Temperature on Microstructure and Tensile Properties of Ti-5.8Al-4.0Sn-4.0Zr-0.7Nb-0.4Si-1.5Ta Near-α Titanium Alloy

2010 ◽  
Vol 97-101 ◽  
pp. 153-157
Author(s):  
Tao Wang ◽  
Hong Zhen Guo ◽  
Jian Hua Zhang ◽  
Ze Kun Yao
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Titanium Alloy ◽  
Tensile Properties ◽  
Room Temperature ◽  
Volume Fraction ◽  
Constant Strain Rate ◽  
Isothermal Forging ◽  
Α Phase ◽  
Transus Temperature

The microstructures and room temperature and 600°C tensile properties of Ti-5.8Al-4.0Sn-4.0Zr-0.7Nb -0.4Si-1.5Ta alloy after isothermal forging have been studied. The forging temperature range was from 850°C to 1075°C, and the constant strain rate of 8×10-3/S-1 was adopted. With the increase of forging temperature, the volume fraction of primary α phase decreased and the lamellar α phase became thicker when the temperatures were in range of 850°C -1040°C; The grain size became uneven and the α phase had different forms when the forging temperature was 1040°C and 1075°C respectively; The tensile strength was not sensitive to the temperature and the most difference was within 20MPa. Tensile strength and yield strength attained to the maximum when temperature was 1020°C; the ductility decreased with the increase of forging temperature, and this trend became more obvious if forging temperature was above the β-transus temperature.

Effects of Extrusion on the Mechanical Properties and Damping Capacity of Mg-1.8Cu-0.5Mn Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 257-260 ◽  
Author(s):  
Zhen Yan Zhang ◽  
Li Ming Peng ◽  
Xiao Qin Zeng ◽  
Lin Du ◽  
Lan Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Room Temperature ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Damping Capacity ◽  
X Ray Diffraction ◽  
Dynamic Mechanical Analyzer ◽  
X Ray ◽  
Solute Atoms

Effects of extrusion on mechanical properties and damping capacity of Mg-1.8wt.%Cu -0.5wt.%Mn (MCM1805) alloy have been investigated. Tensile tests and dynamic mechanical analyzer were respectively used to measure tensile properties and damping capacity at room temperature of as-cast and as-extruded MCM1805 alloy. The microstructure was studied using optical microscope, X-ray diffraction and scanning electron microscope with an energy dispersive X-ray spectrometer. Granato-Lücke model was used to explain the influences of extrusion on damping capacity of MCM1805 alloy. The results showed that extrusion dramatically decreases the grain size but has little influence on phase composition and solute atoms concentration of MCM1805 alloy, and the grain refinement was the dominant reason for the obvious increase of tensile properties and decrease of internal friction of MCM1805 alloy.

Effect of High Temperature Caliber Rolling on Microstructure and Room Temperature Tensile Properties of Mg-3Al-1Zn (AZ31) Alloy

2013 ◽  
Vol 209 ◽  
pp. 6-9 ◽  
Author(s):  
Rajendra Doiphode ◽  
S.V.S. Narayana Murty ◽  
Nityanand Prabhu ◽  
Bhagwati Prasad Kashyap
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Yield Strength ◽  
Strain Rate ◽  
Tensile Properties ◽  
Room Temperature ◽  
Tensile Tests ◽  
Az31 Alloy ◽  
Rolling Temperature ◽  
Grain Sizes

Mg-3Al-1Zn (AZ31) alloy was caliber rolled at 250, 300, 350, 400 and 450 °C. The effects of caliber rolling temperature on the microstructure and tensile properties were investigated. The room temperature tensile tests were carried out to failure at a strain rate of 1 x 10-4s-1. The nature of stress-strain curves obtained was found to vary with the temperature employed in caliber rolling. The yield strength and tensile strength followed a sinusoidal behaviour with increasing caliber rolling temperature but no such trend was noted in ductility. These variations in tensile properties were explained by the varying grain sizes obtained as a function of caliber rolling temperature.

Plasticity-Induced Martensitic Phase Transformation in Fatigue of Unnotched SUS304 Plates

2005 ◽  
Vol 297-300 ◽  
pp. 1152-1157
Author(s):  
Yoshifumi Iwasaki ◽  
Yuji Nakasone
Keyword(s):  
Phase Transformation ◽  
Fatigue Life ◽  
Room Temperature ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Martensitic Phase ◽  
Martensitic Phase Transformation ◽  
Air Volume ◽  
Maximum Value ◽  
Residual Fatigue

The present study has investigated plasticity-induced martensitic phase transformation in fatigue of unnotched SUS304 plates. Martensitic phase transformation occurred in uunotched SUS304 plate specimens fatigued at room temperature in air. Volume fraction Va’ of a’ martensite in the uunotched portion of fatigued specimens was measured by ferrite scope. The relations between the maximum value of Va’, Va’max, and the number of load cycles N were represented by reverse sigmoidal curves for all the applied stress range Ds levels tested in this study. For the most portion of fatigue life, the value of Va’max remained almost constant. This value was increased with increase in the value of Ds. The spatial distribution of Va’ in the specimens varied with N: i.e., continued cycling of stress made a’ transformation localized near the central portion of specimens where the Va’ value reached as high as 35-40%. This value is more than doubled compared to the highest Va’ value found in the tensile tests of SUS304 at room temperature in air. Invisible cracks of 200µm in length were found in the high Va’ value region. These results imply that the measurement of Va’ in fatigued SUS304 components may detect crack initiation sites and may predict residual fatigue life.

Cyclic Stress-Strain Response of Superelastic Polycrystalline Cu-12wt%Al-0.5wt%Be Alloy

2010 ◽  
Vol 643 ◽  
pp. 91-97
Author(s):  
Fabio José Carvalho França ◽  
Nilmário Galdino Guedes ◽  
Severino Jackson Guedes de Lima ◽  
Tadeu Antônio de Avezedo Melo ◽  
Rodinei Medeiros Gomes
Keyword(s):  
Residual Strain ◽  
Room Temperature ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Cyclic Stress ◽  
Applied Strain ◽  
Strain Response ◽  
Loading And Unloading ◽  
Total Volume Fraction ◽  
The Stability

The effect of cyclic deformation on the stability of superelasticity was investigated for the Cu-12wt%Al-0.5wy%Be alloy. The loading and unloading cyclic tensile tests were performed at room temperature and at 57oC with the maximum constant strain of 4%. The effect of holding the applied strain for a period of time on the superelastic properties was also investigated. It was confirmed that the total volume fraction of the retained martensite changes with time after unloading cycle, leading to the reduction of the residual strain. Additionally, the residual strain increases as the loading cycle of the applied strain is kept constant for a period of time.

scholarly journals Tensile Properties of Pandanus Atrocarpus based Composites

1970 ◽  
Vol 1 (1) ◽  
Author(s):  
Hoo Tien Nicholas Kuan ◽  
Meng Chuen Lee
Keyword(s):  
Tensile Properties ◽  
Composite Laminates ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Natural Fibre ◽  
Engineering Industry ◽  
Strength Increase ◽  
Fibre Reinforcement ◽  
Compression Moulding ◽  
Composite Fabrication

Pandanus atrocarpus, or locally known as mengkuang plant is likely to be potential natural fibre reinforcement in composite. Both the Pandanus leaves, and fibres extracted from the Pandanus leaves were used in composite fabrication. Fibres were extracted from Pandanus leaves with water retting process. Pandanus composites were laminated using compression moulding method. The tensile properties of composite laminates based on lamination of Pandanus leaf- and extracted Pandanus fibre-reinforced polyethylene were investigated. Tensile tests have shown that composite laminates based on extracted Pandanus fibre reinforced polyethylene were more superior than using the Pandanus leaf itself without extracting its fibre. Tests exhibited that increasing the volume fraction of Pandanus fibre resulted in strength increase. This suggests that Pandanus fibre- based composites could offer a range of mechanical properties for use in the engineering industry.

scholarly journals Investigation of Slow Eutectoid Element on Tensile Properties and Superplasticity of a Forged SP700 Titanium Alloy

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1852
Author(s):  
Dong Han ◽  
Yongqing Zhao ◽  
Weidong Zeng ◽  
Junfeng Xiang
Keyword(s):  
Tensile Properties ◽  
Room Temperature ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Microstructure Characteristics ◽  
Density Of Dislocations ◽  
Globular Microstructure ◽  
Β Phase ◽  
Elevated Temperature Tensile ◽  
Cr Addition

The tensile properties and superplasticity of a forged SP700 alloy with slow eutectoid element (1.5%Cr) addition were investigated in the present paper. The results of the microstructures showed that slow eutectoid element Cr has a significant influence on stabilizing the β phase and the SP700Cr alloy showed a uniform duplex and completely globular microstructure after annealing at 820 °C for 1 h and aging at 500 °C for 6 h. The results of the tensile tests showed that the yield strength, ultimate tensile strength and elongation of the alloy with optimized microstructure were 1312 MPa, 1211 MPa and 10% at room temperature, and the elongation was achieved to 1127% at 770 °C. Compared with that of the SP700 alloy, the strain rate sensitivity of the SP700Cr alloy showed a higher value. The microstructures after elevated temperature tensile tests showed that the higher density of dislocations and twins exists in SP700 alloy and the lower density of dislocations favor distribution in SP700Cr alloy. Based on the above results, the tensile properties and superplasticity of the forged SP700 alloy with 1.5% Cr addition was analyzed. In addition, microstructure characteristics were investigated by the TEM and EBSD technologies.

Study on the Influence of Compression Damage on Tensile Properties in Fully Lamellar TiAl-Based Alloy

2012 ◽  
Vol 482-484 ◽  
pp. 1713-1717
Author(s):  
Bin Tang ◽  
Chuan Jing Chen ◽  
Zhi Yong Xue ◽  
Chun Jing Wu ◽  
Shuang Shou Li
Keyword(s):  
Mechanical Property ◽  
High Temperature ◽  
Tensile Properties ◽  
Tensile Property ◽  
Room Temperature ◽  
Tial Alloy ◽  
Tensile Tests ◽  
Fully Lamellar ◽  
Compression Damage

The changes of the tensile properties of the full lamellar TiAl alloy under pre-compression were studied by means of pre-compression damage tests and tensile tests. The study indicated that：The changes of the tensile property of the damaged alloy at room temperature were different from that of high temperature. The mechanical property of the TiAl alloy degrades because of the present of the cracks, which decrease the load area of the alloy.

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