scholarly journals Accelerated degradation of polyetheretherketone and its composites in the deep sea

2018 ◽  
Vol 5 (4) ◽  
pp. 171775 ◽  
Author(s):  
Hao Liu ◽  
Jianzhang Wang ◽  
Pengfei Jiang ◽  
Fengyuan Yan

The performance of polymer composites in seawater, under high hydrostatic pressure (typically few tens of MPa), for simulating exposures at great depths in seas and oceans, has been little studied. In this paper, polyetheretherketone (PEEK) and its composites reinforced by carbon fibres and glass fibres were prepared. The seawater environment with different seawater hydrostatic pressure ranging from normal pressure to 40 MPa was simulated with special equipment, in which the seawater absorption and wear behaviour of PEEK and PEEK-based composites were examined in situ . The effects of seawater hydrostatic pressure on the mechanical properties, wear resistance and microstructure of PEEK and its composites were focused on. The results showed that seawater absorption of PEEK and its composites were greatly accelerated by increased hydrostatic pressure in the deep sea. Affected by seawater absorption, both for neat PEEK and composites, the degradation on mechanical properties, wear resistance and crystallinity were induced, the degree of which was increasingly serious with the increase of hydrostatic pressure of seawater environment. There existed a good correlation in an identical form of exponential function between the wear rate and the seawater hydrostatic pressure. Moreover, the corresponding mechanisms of the effects of deep-sea hydrostatic pressure were also discussed.

2014 ◽  
Vol 66 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Serkan Büyükdoğan ◽  
Süleyman Gündüz ◽  
Mustafa Türkmen

Purpose – The paper aims to provide new observations about static strain ageing in aluminium (Al) alloys which are widely used in structural applications. Design/methodology/approach – The present work aims to provide theoretical and practical information to industries or researchers who may be interested in the effect of static strain ageing on mechanical properties of Al alloys. The data are sorted into the following sections: introduction, materials and experimental procedure, results and discussion and conclusions. Findings – Tensile strength, proof strength (0.2 per cent) and percentage elongation measurement were used to investigate the effect of strain ageing on the mechanical properties. Wear tests were performed by sliding the pin specimens, which were prepared from as-received, solution heat-treated, deformed and undeformed specimens after ageing, on high-speed tool steel (64 HRC). It is concluded that the variations in ageing time improved the strength and wear resistance of the 6063 Al alloy; however, a plastically deformed solution-treated alloy has higher strength and wear resistance than undeformed specimens for different ageing times at 180°C. Practical implications – A very useful source of information for industries using or planning to produce Al alloys. Originality/value – This paper fulfils an identified resource need and offers practical help to the industries.


2021 ◽  
Vol 118 (6) ◽  
pp. 606
Author(s):  
Nandish Girishbhai Soni ◽  
Akash Ganesh Mahajan ◽  
Kaustubh Ramesh Kambale ◽  
Sandeep Prabhakar Butee

Fabrication with the in-situ formation of W2C reinforced medium carbon steel (MCS) MMC’s was attempted using W or WO3 and graphite addition to steel. The P/M route comprising milling, compaction and sintering at 1050 °C and 1120 °C respectively in 90% N2 + 10% H2 atmosphere was adopted. Both SEM and BET studies revealed the particle size to be around 100, 7 and 40 µm for MCS, W and WO3, respectively. A complete conversion of tungsten into tungsten semicarbide (W2C) was noted in XRD for the tungsten additions of ∼6, 9 and 12 wt.% with stoichiometrically balanced C (graphite) addition of 0, 0.2 and 0.4 wt.%. However, WO3 + C addition (balanced as above) revealed the partial conversion of WO3 to W2C. The peaks of Fe3C were observed only for MCS + W + C samples and not for MCS + WO3 + C samples in XRD. In SEM, the WO3 phase appeared porous and partially converted, whereas, W2C phase was dense. Sintered density improved for the addition of W, whereas it monotonically reduced for WO3 addition to MCS + C samples. Higher hardness, compressive strength, and wear resistance was noted for W addition than WO3 to MCS+C samples.


Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1121 ◽  
Author(s):  
Li ◽  
Liang ◽  
Tian ◽  
Yang ◽  
Xie ◽  
...  

Titanium composite strengthened by Ti3Al precipitations is considered to be one of the excellent materials that is widely used in engineering. In this work, we prepared a kind of Ti-Ti3Al metallic composite by in-situ synthesis technology during the SLM (selective laser melting) process, and analyzed its microstructure, wear resistance, microhardness, and compression properties. The results showed that the Ti-Ti3Al composite, prepared by in-situ synthesis technology based on SLM, had more homogeneous Ti3Al-enhanced phase dispersion strengthening structure. The grain size of the workpiece was about 1 μm, and that of the Ti3Al particle was about 200 nm. Granular Ti3Al was precipitated after the aluminum-containing workpiece formed, with a relatively uniform distribution. Regarding the mechanical properties, the hardness (539 HV) and the wear resistance were significantly improved when compared with the Cp-Ti workpiece. The compressive strength of the workpiece increased from 886.32 MPa to 1568 MPa, and the tensile strength of the workpiece increased from 531 MPa to 567 MPa after adding aluminum. In the future, the combination of in-situ synthesis technology and SLM technology can be used to flexibly adjust the properties of Ti-based materials.


2015 ◽  
Vol 25 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Fei CHEN ◽  
Tong-min WANG ◽  
Zong-ning CHEN ◽  
Feng MAO ◽  
Qiang HAN ◽  
...  

2011 ◽  
Vol 326 ◽  
pp. 144-150
Author(s):  
A. Mateen ◽  
Fazal Ahmad Khalid ◽  
T.I. Khan ◽  
G.C. Saha

Tungsten carbide cobalt coating has been extensively used for cutting and mining tools, aerospace, automotive and other wear resistance applications. These coatings not only have superior mechanical properties like high hardness, toughness and compressive strength but have also excellent controllable tribological properties. In this paper a comparison of wear properties and structural phases has been presented to consider for tribological applications. It is found that nanocrystalline duplex coatings have shown much superior properties as compared to the microcrystalline coatings. Evidence of clusters of WC particles was found in microcrystalline coating as compared to homogeneous dense coating structure observed in the nanocrystalline coating. These results are discussed to assess their suitability for super hard wear resistance applications.


2011 ◽  
Vol 20 (4) ◽  
pp. 096369351102000 ◽  
Author(s):  
Ferit Ficici ◽  
Sakip Koksal ◽  
Ramazan Kayikci ◽  
Omer Savas

In this study, wear behaviour of AlB2/Al composite materials produced through in-situ method have been experimentally investigated. Four different composite materials that include 5wt.%, 10wt.%, 20wt.% and 30wt.% AlB2 reinforcement phase were tested using pin-on-disk arrangement. The effects of the rate of reinforcement on wear and friction behaviours have been investigated. Wear tests are carried out at 1.83, 3.40 and 4.71 m/s sliding speeds under 10, 20 and 40 N applied loads. The test results show that wear rate increases with the increase in applied load and sliding distance. Increasing the rate of reinforcement phase in the matrix has proportionally increased the wear resistance by 3% to 30%. Hence the greatest wear resistance has been observed with the composite materials having 30wt. % AlB2 reinforcement. Analysis of the worn surfaces of composite samples shows that abrasive and adhesive wear mechanisms are more effective.


Wear ◽  
2011 ◽  
Vol 270 (9-10) ◽  
pp. 640-649 ◽  
Author(s):  
Nicolas Serres ◽  
Françoise Hlawka ◽  
Sophie Costil ◽  
Cécile Langlade ◽  
Frédérique Machi

2011 ◽  
Vol 462-463 ◽  
pp. 307-312 ◽  
Author(s):  
Mahamad Noor Wahab ◽  
Mariyam Jameelah Ghazali ◽  
Abdul Razak Daud

The effect of AlN addition in Al-Si alloy composites on the mechanical properties and dry wear behaviour were studied using pre-selected parameter conditions. In this work, high purity of AlN powders with different weight percentage of 5, 7 and 10 were used as reinforced materials for the composites. Morphology of the reinforced composite indicated that both silicon grains and inter-metallic compounds were surrounded by the AlN particles. The presence of AlN in the Al-Si alloy showed a significant improvement in tensile properties in which 7wt% of AlN addition increased up to 25% compared to those of without any reinforcements. Fracture morphologies with small dimples, tear ridges and necking features indicated that ductile fractures had occurred on the Al-Si composites. At 25N load, alloys with 5wt% of AlN exhibited high wear resistances whereas at 70N, alloys with 10wt% of AlN showed a great improvement in wear resistance. SEM investigation also revealed that the presence of wear was also marked with prominent grooves, craters and scoring marks. Overall, alloys with 7wt% AlN addition possessed great improvement in hardness, tensile and wear resistance properties.


2014 ◽  
Vol 11 (2) ◽  
pp. 139-146
Author(s):  
Anna Porąbka ◽  
Vasiliki-Maria Archodoulaki ◽  
Wolfgang Molnar ◽  
Jadwiga Laska

Two series of polyurethane matrix composites were prepared. As generally resistant to wear, the PUs can be used as matrices for wear protective and load-bearing composites. The objective of this study was to compare the mechanical properties of composites containing 5% vol. of selected ceramic particles, and unmodified PUs. The effect of various particles on physical and mechanical properties was studied. The results showed that the mechanical properties changed compared to reference materials: modulus improved in certain materials and in different temperatures, revealing the favourable influence of FA and SiO2 particles. In turn, Rm and wear resistance decreased with the type and shape of filler.


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