پلاستیک ها، الاستومر ها و کامپوزیت ها به منظور کنترل خوردگی

 Using Plastics, Elastomers, and Composites for Corrosion Control

استفاده از پلاستیک ها، الاستومر ها و کامپوزیت ها به منظور کنترل خوردگی 

ABSTRACT

This chapter provides a broad overview of the application of polymers used for corrosion control in the chemical proces- sing industry. The generalizations offered about polymer performance might suggest possible approaches, but they should not be considered as recommendations owing to the complexity of equipment design and the many variables of chemical processing. Consultations with experts, analyses of case histories, and testing are essential to the success of these materials.

 

تولید کامپوزیت‌های B4C-TiB2 با پرس گرم

Microstructure and mechanical properties of B4C–TiB2

composites prepared by reaction hot pressing using Ti3SiC2

ریزساختار و خواص مکانیکی کامپوزیت‌های B4C-TiB2 تولیدشده توسط پرس گرم

با استفاده از Ti3SiC2 به عنوان افزودنی

ABSTRACT

B4C–TiB2 composites were fabricated via reaction hot pressing at 2100 °C under a pressure of 25 MPa, using B4C and Ti3SiC2 powders as raw materials. The phase transformations, microstructure and mechanical properties were investigated by XRD, TG–DTA, SEM, TEM and EDS. It is found that the SiC and TiB2 particles are homogenously dispersed in the B4C–TiB2 composites, where nano-sized TiB2 particles are mainly located within the B4C matrix grains, while the large-sized TiB2 particles at the matrix grains boundaries. Due to the pinning effect of SiC and TiB2 particles on B4C grain growth, the grain size of the composite is significantly reduced, leading to a great improvement of the mechanical properties. B4C–TiB2 composite prepared from B4C-10 wt% Ti3SiC2 starting powder shows high flexural strength, fracture toughness and micro-hardness of 592 MPa, 7.01 MPa m1/2 and 3163 kg/mm2, respectively. Crack deflection and crack bridging are most likely the potential toughening mechanisms in the composites. Furthermore, according to the XRD and TG–DTA analysis, the possible reaction mechanisms leading to the in-situ formation of TiB2 were proposed.

متالورژی پودر بیوکامپوزیت Ti35Nb2.5Sn و زینترسازی

Effect of milling time on microstructure of Ti35Nb2.5Sn/10HA

biocomposite fabricated by powder metallurgy and sintering

تاثیر زمان آسیاب کردن بر ریزساختار بیوکامپوزیت Ti35Nb2.5Sn/10HA

تولید‌شده با متالورژی پودر و زینتر‌سازی

ABSTRACT

A new β-Ti based Ti35Nb2.5Sn/10 hydroxyapitite (HA) biocompatible composite was fabricated by mechanical milling and pulsed current activated sintering(PCAS). The microstructures of Ti35Nb2.5Sn/10HA powder particles and composites sintered from the milled powders were studied. Results indicated that α-Ti phase began to transform into β-Ti phase after the powders were mechanically milled for 8 h. After mechanical milling for 12 h, α-Ti completely transformed into β-Ti phase, and the ultra fine Ti35Nb2.5Sn/10HA composite powders were obtained. And ultra fine grain sized Ti35Nb2.5Sn/10HA sintered composites were obtained by PCAS. The hardness and relative density of the sintered composites both increased with increasing the ball milling time.

 

ساختار و استحکام کامپوزیت کربن- تقویت شده با کربن

Strength and structure of carbon–carbon reinforced composite

ساختار و استحکام کامپوزیت کربن- تقویت شده با کربن

ABSTRACT

The atomistic simulations of carbon nanotube (CNT) – carbon reinforced composite material are reported. The studied composite samples are obtained by impregnating certain amounts of CNTs (3,3) and (6,6) into a pristine graphite matrix. The addition of CNTs is found to be of significant usefulness for the CNT–reinforced composites, since it allows to achieve extreme lightness and strength. Being impregnated into graphite matrix, CNTs are able to increase the critical component of its initially highly anisotropic Young modulus by 2–8 times. The linear thermal expansion coefficients do not exceed 10−6 to 10−5 K−1, making this material applicable for novel aviation and space vehicles. The degree of dispersion of CNTs within graphite matrix is found to drastically influence composite properties.

 

چاپ سه بعدی کامپوزیت کربن/کربن توسط زینتر لیزر انتخابی

Three dimensional printing of carbon/carbon composites

by selective laser sintering

چاپ سه بعدی کامپوزیت کربن/کربن توسط زینتر لیزر انتخابی

ABSTRACT

A novel three dimensional (3D) printing method is developed to fabricate complex carbon/carbon (C/C) composite components. The C/C composites with the high mechanical performance are achieved by combining the selective laser sintering and the chemical vapor infiltration-thermal treatment process. The C/C composites with a maximum density of 1.5 g/cm3 and bending strength of 100 MPa are obtained. Complex C/C composite parts with the minimum thickness of 0.5 mm are accurately fabricated with the computer-aided design technique. This developed 3D printing method can be well applied to the production of complex C/C composite parts with high precision and good mechanical performance.

 

رفتار اصطکاکی و سایشی کامپوزیت های سرامیک- آلیاژ آلومینیوم

Friction and Wear Behaviour of Brake Pads Dry Sliding Against

Semi-Interpenetrating Network Ceramics/Al-alloy Composites

رفتار اصطکاکی و سایشی ناشی از سایش خشک لنت های ترمز بر روی

شبکه نیمه نفوذی کامپوزیت های سرامیک/ آلیاژ آلومینیومی 

ABSTRACT

Semi-interpenetrating network composites containing 40 vol.% ceramics (5Al2O3·8SiO2) and 60 vol.% Al-alloy were fabricated in place of cast iron available for automotive brake rotors. The friction and wear performances of brake pads dry sliding against the composites were measured using a SRV testing machine. The test procedures include friction fade and recovery, load sensitivity at 100 and 250°C, and wear. The friction was found to increase first and then decrease with increasing temperature, followed by the inverse recovery upon cooling. Wear showed an incremental tendency over a wide temperature range. For loads from 40 to 160 N, the friction decreased at 100 and 250°C. At load below 128 N, the former friction was inferior to the latter while at load above 128 N the friction exhibited an inverse tendency. Wear mildly increased with load at 100 °C and decreased dramatically at 250 °C. SEM and EDS investigations revealed that the worn pad surfaces at 250 °C were covered by more tribofilms, including more coke and graphite with friction-reducing action as well as fewer compounds (corresponding to Si and Al) with friction-increasing action in comparison with those at 100 °C. The compression of the tribofilms contributed to a large decrease in the friction and wear with increasing load. However, at 100 °C E-glass fibers exposed at the worn surfaces inhibited the excessive wear of the pad despite lack of more tribofilms. Their glossy surfaces decreased the friction. The proposed friction models explain some friction and wear behaviour better.

 

مدل‎های چند مقیاسی از کامپوزیت‎های زمینه سرامیکی بافته شده

Multiscale model of woven ceramic matrix composites

considering manufacturing induced damage

مدل‎های چند مقیاسی از کامپوزیت‎های زمینه سرامیکی بافته شده

با توجه به آسیب‎های ایجاد شده‎ی تولید

ABSTRACT

Multiscale models play an important role in capturing the nonlinear response of woven carbon fiber reinforced ceramic matrix composites. In plain weave carbon fiber/silicon carbide (C/SiC) composites, for example, when microcracks form in the as-produced parts due to the mismatch in thermal properties between constituents, a multiscale thermoelastic framework can be used to capture the initial damage state of these composites. In this paper, a micromechanics-based multiscale model coupled with a thermoelastic progressive damage model is developed to simulate the elastic and damage behavior of a plain weave C/SiC composite system under thermal and mechanical loading conditions. The multiscale model is able to accurately predict composite behavior and serves as a valuable tool in investigating the physics of damage initiation and progression, in addition to the evolution of effective composite elastic moduli caused by temperature change and damage. The matrix damage initiation and progression is investigated at various length scales and the effects are demonstrated on the global composite behavior.

 

کامپوزیت‎های تقویت شده با الیاف سه بعدی فیبر شیشه-پلی پروپیلن

Polypropylene/glass fibre 3D-textile reinforced composites

for automotive applications

کامپوزیت‎های تقویت شده با الیاف سه بعدی فیبر شیشه/پلی پروپیلن

برای کاربردهای خودرو

ABSTRACT

Textile-reinforced thermoplastic composites offer huge application potentials for a rapid manufacturing of components with versatile possibilities of integrating functions. However, an application of these new materials requires the knowledge of the directional dependent material properties. In this study, results are presented concerning selected relevant load cases for industrial applications. For the new group of multi-layered flat bed weft-knitted glass fibre/polypropylene composites (MKF-GF/PP), tensile tests under different temperatures and test velocities have been carried out as well as Charpy impact tests, open hole tension tests and dynamic-mechanical analysis. The mechanical properties of MKF-GF/PP and unidirectional GF/PP composites with tailored fibre surface and interphase, respectively, have been compared to those of woven GF/PP composites and GF/PP composites made of non-crimp fabrics (NCF) as a benchmark.

 

کامپوزیت‎های تقویت شده با الیاف سه بعدی فیبر شیشه-پلی پروپیلن

Polypropylene/glass fibre 3D-textile reinforced composites

for automotive applications

کامپوزیت‎های تقویت شده با الیاف سه بعدی فیبر شیشه/پلی پروپیلن

برای کاربردهای خودرو

ABSTRACT

Textile-reinforced thermoplastic composites offer huge application potentials for a rapid manufacturing of components with versatile possibilities of integrating functions. However, an application of these new materials requires the knowledge of the directional dependent material properties. In this study, results are presented concerning selected relevant load cases for industrial applications. For the new group of multi-layered flat bed weft-knitted glass fibre/polypropylene composites (MKF-GF/PP), tensile tests under different temperatures and test velocities have been carried out as well as Charpy impact tests, open hole tension tests and dynamic-mechanical analysis. The mechanical properties of MKF-GF/PP and unidirectional GF/PP composites with tailored fibre surface and interphase, respectively, have been compared to those of woven GF/PP composites and GF/PP composites made of non-crimp fabrics (NCF) as a benchmark.

 

مواد کامپوزیت نساجی : کامپوزیت های زمینه پلیمری

Textile Composite Materials: Polymer Matrix Composites

مواد کامپوزیت نساجی : کامپوزیت های زمینه پلیمری

ABSTRACT

Textile composites are fiber-reinforced composite materials, the reinforcement being in the form of a textile fabric (woven, knitted, braided). In the production of composite parts, the use of textile reinforcements brings benefits in handability of the fabrics (hence in automation possibilities and in cost) and in easier applicability of closed-mold processes. In performance, due to interlacing of yarns in textile, the interlaminar/ through-the-thickness/ impact properties of composite are improved; matrix cracks, originated inside the yarns, do not propagate through the material but are stopped when the yarn changes its direction. The latter mechanism leads to higher-energy absorption capabilities in crash-resistant applications