scholarly journals Effect of Polyacrylonitrile Precursor Orientation on the Structures and Properties of Thermally Stabilized Carbon Fiber

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3237
Author(s):  
Bin Wang ◽  
Chenggao Li ◽  
Weiyu Cao
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Carbon Fiber ◽  
Yield Strength ◽  
Thermal Stabilization ◽  
Precursor Fiber ◽  
Orientation Degree ◽  
Stabilization Process ◽  
Orientation Structure ◽  
Pan Fibers

The thermal stabilization process of polyacrylonitrile (PAN) precursor fiber was the key step to prepare high-performance carbon fiber. During the thermal stabilization process, the aggregation structure and the reactivity of molecular chains have significant effects on the microstructures and mechanical properties of carbon fiber. In the present paper, the effects of the orientation structure of PAN precursor fiber on the thermal stabilization reaction and the mechanical properties of carbon fiber were experimentally studied. Using multi-dimensional structural and mechanical properties tests, such as XRD, DSC, 13C NMR and Instron machine testing, the crystalline and skeleton structure, exothermic behavior, and tensile properties of PAN precursor fiber with different orientations in the process of thermal stabilization were characterized to reveal the relationship between microstructure evolution and tensile properties. The results showed that the orientation structure of PAN precursor fiber had an obvious effect on the thermal stabilization process and the tensile stress–strain characteristic. When the heat treatment temperature was lower than 200 °C, the crystallinity and crystallite size of PAN fibers with higher orientation degrees increased significantly. After sufficient thermal stabilization, the original PAN precursor fiber with a higher orientation degree could form more aromatic lamellar structures and showed better regularity. Furthermore, the yield strength and initial modulus of the fibers with a higher orientation degree increased due to the formation of more aromatic rings. The maximum increase in the percentages of yield strength and tensile modulus of the PAN fibers were achieved when the heat-treated temperature was 200 °C, and the percentage values were 138.4% and 158.7% compared to the precursor without heat-treatment. In addition, the elongation at break of the fibers with a higher orientation degree was also relatively larger.

Effect of Heat Treatment on Mechanical Properties of Laminated Carbon Fiber Reinforced Polymeric Composites

2016 ◽  
Author(s):  
A. B. M. I. Islam ◽  
Ajit D. Kelkar ◽  
Lifeng Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Fiber Surface ◽  
Fiber Reinforced ◽  
Carbon Fabric ◽  
Carbon Fiber Reinforced ◽  
Fiber Deposition ◽  
Pan Fibers

In recent years use of electrospun nanofibers and nanoparticles to improve the interlaminar properties have increased significantly. In most of the cases the additional interlaminar phase of nanofibers is required to go through various thermal and/or chemical processes. There has been emphasis to optimize the interlaminar nanofiber layers to achieve the optimum desired mechanical properties such as interlaminar strength. One common practice is to disperse nanofibers into the resin and then use the nanofiber enhanced resin to fabricate the laminated composites. However, proper dispersion and fiber filtering out are some of the problems that exist in fabrication using the nanofiber mixed resin approach. To alleviate this problem, an innovative approach of growing PAN (polyacrylnitrile) nano fibers directly on carbon fabric by electrospinning seems to solve the dispersion and fiber filtering problem. However, as PAN fibers require stabilization and carbonization, it is obvious that carbon fabric with PAN fiber deposition will have to undergo stabilization and carbonization process. The effect of stabilization and carbonization heat treatment on the mechanical properties of carbon fiber fabric is not yet fully understood. This paper presents the effects of heat treatment on carbon fabric used for fabricating laminated carbon fiber reinforced composite with epoxy resin. The heat treatment was performed at 280°C in air for six hours, and 1200°C for one hour in nitrogen which are similar to stabilization and carbonization of pure PAN fibers. The effects, due to heat treatment, were mainly characterized in terms of mechanical properties by performing tensile tests and shear tests. Fiber surface topography was observed by SEM to analyze physical changes. Chemical changes, corresponding to the existing groups with carbon fibers, were examined through FTIR. The results obtained are compared with a set of control laminated composite specimens, which were fabricated using heat vacuum assisted resin transfer molding (HVARTM) process and cured at 149°C. The two sets of composite were infused with resin in a single vacuum bag to ensure that both sets of specimens have identical resin infusion and cure cycle. Laminates used for making control specimens were fabricated using carbon fabric which did not undergo any heat treatment. A change in laminate thickness for heat treated carbon fabric was observed indicating a possible bulk up of the carbon fibers due to loss of sizing compounds, which also resulted into significant change in tensile properties.

Effect of Different Heat Treatments on Mechanical Properties of Laser Sintered Additive Manufactured Parts

2017 ◽  
Author(s):  
Sagar Sarkar ◽  
Cheruvu Siva Kumar ◽  
Ashish Kumar Nath
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Yield Strength ◽  
Tensile Strain ◽  
Wear Loss ◽  
Layer By Layer ◽  
Solution Annealing ◽  
Wear Properties ◽  
Sem Images ◽  
Wide Range

One of the most popular additive manufacturing processes is laser based direct metal laser sintering process which enables us to make complex three dimensional parts directly from CAD models. Due to layer by layer formation, parts built in this process tend to be anisotropic in nature. Suitable heat treatment can reduce this anisotropic behaviour by changing the microstructure. Depending upon the applications, a wide range of mechanical properties can be achieved between 482–621° C temperature for precipitation-hardened stainless steels. In the present study effect of different heat treatment processes, namely solution annealing, ageing and overaging, on tensile strength, hardness and wear properties has been studied in detail. Suitable metallurgical and mechanical characterization techniques have been applied wherever required, to support the experimental observations. Results show H900 condition gives highest yield strength and lowest tensile strain at break whereas solution annealing gives lowest yield strength and as-built condition gives highest tensile strain at break. SEM images show that H900 and H1150 condition produces brittle and ductile morphology respectively which in turn gives highest and lowest hardness value respectively.XRD analysis shows presence of austenite phases which can increase hardness at the cost of ductility. Average wear loss for H900 condition is highest whereas it is lowest for solution annealed condition. Further optical and SEM images have been taken to understand the basic wear mechanism involved.

PAN precursor fabrication, applications and thermal stabilization process in carbon fiber production: Experimental and mathematical modelling

2020 ◽  
Vol 107 ◽  
pp. 100575 ◽  
Author(s):  
Hamid Khayyam ◽  
Reza N. Jazar ◽  
Srinivas Nunna ◽  
Gelayol Golkarnarenji ◽  
Khashayar Badii ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Mathematical Modelling ◽  
Thermal Stabilization ◽  
Fiber Production ◽  
Stabilization Process

Microstructure and Mechanical Properties of TiB2/ Al-Si Composites Fabricated by TIG Wire and Arc Additive Manufacturing

2019 ◽  
Vol 944 ◽  
pp. 64-72
Author(s):  
Qing Feng Yang ◽  
Cun Juan Xia ◽  
Ya Qi Deng
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Yield Strength ◽  
Filler Wire ◽  
T6 Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
Before And After

Bulky sample was made by using TIG wire and arc additive manufacturing (WAAM) technology, in which Ф1.6 mm filler wire of in-situ TiB2/Al-Si composites was selected as deposition metal, following by T6 heat treatment. The microstructure and mechanical properties of the bulky sample before and after heat treatment were analyzed. Experimental results showed that the texture of the original samples parallel to the weld direction and perpendicular to the weld direction was similar consisting of columnar dendrites and equiaxed crystals. After T6 heat treatment, the hardness of the sample was increased to 115.85 HV from 62.83 HV, the yield strength of the sample was 273.33 MPa, the average tensile strength was 347.33 MPa, and the average elongation after fracture was 7.96%. Although pore defects existed in the fracture, yet the fracture of the sample was ductile fracture.

scholarly journals A Pathway to Reduce Energy Consumption in the Thermal Stabilization Process of Carbon Fiber Production

Energies ◽  
2018 ◽  
Vol 11 (5) ◽  
pp. 1145 ◽  
Author(s):  
Srinivas Nunna ◽  
Maxime Maghe ◽  
Seyed Fakhrhoseini ◽  
Bhargav Polisetti ◽  
Minoo Naebe
Keyword(s):  
Energy Consumption ◽  
Carbon Fiber ◽  
Thermal Stabilization ◽  
Fiber Production ◽  
Stabilization Process ◽  
Reduce Energy Consumption

Microstructure and Mechanical Properties of Ti-6Al-4V Alloy Samples Fabricated by Selective Laser Melting

2018 ◽  
Vol 770 ◽  
pp. 179-186 ◽  
Author(s):  
Jing Bo Gao ◽  
Xiao Li Zhao ◽  
Ju Kun Yue ◽  
Meng Chao Qi ◽  
De Liang Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Crystal Growth ◽  
Yield Strength ◽  
Selective Laser Melting ◽  
Lamellar Structure ◽  
Growth Direction ◽  
Laser Melting ◽  
Α Phase ◽  
Dog Bone

Ti-6Al-4V (wt%) alloy samples with dog-bone and box shapes respectively were fabricated by selective laser melting (SLM). The microstructures and mechanical properties of the 3D printed Ti-6Al-4V samples with and without heat treatment were characterized and tested. The microstructures of the as-fabricated dog-bone shaped samples were mainly composed of acicular α’ phase. After annealing at 700°C, the acicular α’ phase changed into an α/β lamellar structure. After solution treatment at 955°C, water quenching and aging at 550°C, the microstructure was mainly composed of primary α phase and α/β lamellar structure. The optimum heat treatment is annealing, and the mechanical properties of the annealed sample are as follows: yield strength: 1015 MPa, ultimate tensile strength (UTS): 1083 MPa and elongation to fracture: 7.9%. The microstructures of the box-shaped samples after annealing mainly consist of α phase and α/β lamellar structure. When stretched along the direction parallel to the crystal growth direction, the yield strength and UTS of the sample are 1054 and 1090 MPa，and its elongation to fracture is 6.3%. When stretched along the direction perpendicular to the crystal growth direction, the yield strength and UTS of the sample are 1019 and 1068 MPa respectively, and its elongation to fracture is 8.7%.

Grain Size Dependence of Tensile Properties in Cu-Sn Thin Foils (Experimental Study)

2015 ◽  
Vol 736 ◽  
pp. 19-23
Author(s):  
Taek Kyun Jung ◽  
Hyo Soo Lee ◽  
Hyouk Chon Kwon
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Experimental Study ◽  
Grain Size ◽  
Yield Strength ◽  
Room Temperature ◽  
Size Dependence ◽  
Yield Drop ◽  
Thin Foils ◽  
Vacuum Atmosphere

This study was carried out to investigate the effects of grain size on mechanical properties in Cu-Sn foil with a thickness of 30 um. The grain size was varied from approximately 7 um to 50 um using heat treatment at 773 K for 2 h to 24 h in a vacuum atmosphere. Tensile test was carried out at room temperature with strain rate of 1mm/min. Typical yield drop phenomenon was observed. Mechanical properties were found to be strongly affected by microstructural features including grain size. The yield strength and tensile strength gradually decreased with increasing the grain size. The strain to fracture also decreased by grain growth. These results could be explained by not only the grain size dependence of yield strength but also the ratio of thickness to grain size dependence of yield strength.

Influence of Heat-Treatment on Properties, Microstructure and Corrosion Resistant of Zirconium Sheet

2014 ◽  
Vol 936 ◽  
pp. 1796-1800
Author(s):  
Peng Dang ◽  
Xiao Wei Zhang ◽  
Yun Wang ◽  
Qing Zhang ◽  
Chang Liang Li
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Yield Strength ◽  
Cold Rolling ◽  
Annealing Temperature ◽  
Experimental Results ◽  
Corrosion Resistant ◽  
Mechanical Properties And Corrosion

The influence of annealing temperature on the microstructure, mechanical properties and corrosion resistant of cold rolling zirconium sheet were studied in the manuscript. The experimental results shown that the tensile strength and yield strength of zirconium sheet were decreased and the elongationwas raised with the raising of annealing temperature from 500 °C to 580 °C. The recrystallization are not happened in zirconium sheet at the annealing temperature of 500 °C. Zirconium sheet complete recrystallized and the strength and elongation get a well match at the annealing temperature of 540°C. Zirconium sheet also complete recrystallized at the annealing temperature of 580°C but the crystalline grain has the tendency of growing. The annealing temperature has no effect on the corrosion resistant of zirconium sheet.

scholarly journals Effect of Heat Treatment on Mechanical Properties and Microstructure Morphology of Low-Alloy High-Strength Steel

2016 ◽  
Vol 61 (2) ◽  
pp. 475-480
Author(s):  
K. Bolanowski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
Strengthening Phase ◽  
Average Grain Size

Abstract The paper analyzes the influence of different heat treatment processes on the mechanical properties of low-alloy high-strength steel denoted by Polish Standard (PN) as 10MnVNb6. One of the findings is that, after aging, the mechanical properties of rolled steel are high: the yield strength may reach > 600 MPa, and the ultimate tensile strength is > 700 MPa. These properties are largely dependent on the grain size and dispersion of the strengthening phase in the ferrite matrix. Aging applied after hot rolling contributes to a considerable rise in the yield strength and ultimate tensile strength. The process of normalization causes a decrease in the average grain size and coalescence (reduction of dispersion) of the strengthening phase. When 10MnVNb6 steel was aged after normalization, there was not a complete recovery in its strength properties.

Effects of Heat Treatment Process on Mechanical Properties of X70 Grade Pipeline Steel Bends

2015 ◽  
Vol 727-728 ◽  
pp. 322-326 ◽  
Author(s):  
Shi Lu Zhao ◽  
Zhen Zhang ◽  
Lian Chong Qu ◽  
Jun Zhang ◽  
Jian Ming Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Yield Strength ◽  
Thermal Insulation ◽  
Treatment Process ◽  
Pipeline Steel ◽  
Impact Testing ◽  
Air Cooling ◽  
Heat Treatment Process

Effects of heat treatment process of quenching and tempering under different temperature conditions on mechanical properties of X70 grade pipeline steel bends were studied. Brinell hardness, yield strength, tensile strength, elongation and impact absorbing energy of the bends were tested by using hardness tester, cupping machine and impact testing machine, respectively. It shows that the best heat treatment process of the X70 grade pipeline steel bends is quenching at 890 °Cand thermal insulation for 26 min then water cooling followed by tempering at 590 °C and thermal insulation for 60 min then air cooling. Furthermore, the resulting hardness, yield strength, tensile strength, yield ratio, elongation and impact absorbing energy reach HB230, 595 MPa, 725 MPa, 0.82, 28% and 300 J respectively, which has excellent comprehensive mechanical properties.

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