Laser Cladding of TiC for Better Titanium Components

Pure commercial titanium is widely used because of its high corrosion resistance and lower cost compared with other titanium alloys, in particular when there is no high wear requirements. Nevertheless, the wear resistance is poor and surface damage usually occurs in areas under contact loadings. Laser cladding is a suitable technique for manufacturing precise and defect free coatings of a dissimilar material with higher wear and corrosion resistance. In this work a good understanding of laser metal deposition mechanisms allowed to obtain defect free coatings of Ti6Al4V and TiC metal matrix composite (MMC) using a flash lamp pumped Nd:YAG laser of 1 kW. A complete investigation of the process parameters is discussed and resultant wear properties are shown. The results show the feasibility to apply the process for manufacturing, improving or repairing high added value components for a wide range of industrial sectors. © 2011 Published by Elsevier Ltd.Sampedro, J.; Pérez, I.; Cárcel González, B.; Ramos, JA.; Amigó Borrás, V. (2011). Laser Cladding of TiC for Better Titanium Components. Physics Procedia. 12(Part A):313-322. doi:10.1016/j.phpro.2011.03.040S31332212Part

3rd International Conference on Tribocorrosion – Atlanta 2012

Editorial provided for a special issue of "Tribology International", which presents research from the 3rd International Conference on Tribocorrosion, Atlanta 2012

Parametric Study on In Situ Laser Powder Bed Fusion of Mo(Si1−x,Alx)2

Mo(Si1−x,Alx)2 composites were produced by a pulsed laser reactive selective laser melting of MoSi2 and 30 wt.% AlSi10Mg powder mixture. The parametric study, altering the laser power between 100 and 300 W and scan speed between 400 and 1500 mm·s−1, has been conducted to estimate the effect of processing parameters on printed coupon samples’ quality. It was shown that samples prepared at 150–200 W laser power and 400–500 mm·s−1 scan speed, as well as 250 W laser power along with 700 mm·s−1 scan speed, provide a relatively good surface finish with 6.5 ± 0.5 µm–10.3 ± 0.8 µm roughness at the top of coupons, and 9.3 ± 0.7 µm–13.2 ± 1.1 µm side surface roughness in addition to a remarkable chemical and microstructural homogeneity. An increase in the laser power and a decrease in the scan speed led to an apparent improvement in the densification behavior resulting in printed coupons of up to 99.8% relative density and hardness of ~600 HV1 or ~560 HV5. The printed parts are composed of epitaxially grown columnar dendritic melt pool cores and coarser dendrites beyond the morphological transition zone in overlapped regions. An increase in the scanning speed at a fixed laser power and a decrease in the power at a fixed scan speed prohibited the complete single displacement reaction between MoSi2 and aluminum, leading to unreacted MoSi2 and Al lean hexagonal Mo(Si1−x,Alx)2 phase

Wpływ udziału węglika WC gruboziarnistego do drobnoziarnistego na właściwości mechaniczne i zużycie ścierne węglików spiekanych WC-8Co

W artykule przedstawiono wyniki badań dotyczących wpływu ilości drobnoziarnistego węglika wolframu na wzmocnienie metalicznego spoiwa kobaltowego (Co) w węgliku spiekanym WC-8Co. Celem badań jest znalezienie optymalnego udziału węglika gruboziarnistego do drobnoziarnistego dla uzyskania poprawy właściwości mechanicznych i charakterystyk zużyciowych. Dla wszystkich próbek zastosowano jednakowy udział spoiwa, by zbadać jedynie wpływ udziału grubo- do drobnoziarnistego węglika w spieku. W wyniku przeprowadzonych badań stwierdzono, że dla proporcji 8:1 udziału węglika grubo- do drobnoziarnistego uzyskuje się najkorzystniejsze cechy użytkowe, tj.: twardość, udarność i odporność na pękanie. Ponadto poprzez dodanie do kompozytu inhibitorów wzrostu, np. węglika wanadu (VC) lub węglika chromu (Cr3C2), zwiększa się odporność na zużycie ścierne w stosunku do kompozytów bez dodatku inhibitorów.This study performs a comprehensive analysis concerning the amount of fine tungsten carbide (WC) grains needed for the appropriate reinforcement of the cobalt (Co) metallic binder in WC-8Co cemented carbides. The goal is to investigate the balance of coarse-to-fine grain distribution to achieve overall improvement of the material’s mechanical and wear properties. All Samales possessed the same WC-8Co binder content, therefore, allowing the role of grain size distribution to be tested. It was found that a ratio of 8:1 wt% of coarse to ultrafine grain WC yielded an appropriate balance between material hardness, fracture toughness, and rupture strength. Upon adding grain growth inhibitors vanadium carbide (VC) and chromium carbide (Cr3C2), the overall wear resistance is further improved compared to undoped composites when Samales are tested under abrasive wear conditions

Hybrid Syntactic Foams of Metal - Fly Ash Cenosphere - Clay

This paper addresses an innovative composite material (CM)- syntactic foam prodecued out of metal powder (Fe), fly ash cenospheres (CS) and clay. Due to the low density of CS (were used as space holder, CS bulk density-0,38 g/cm3), the average density of these foams is about 2,6-2,9 g/cm3. It was found that CS undergoes phase transformation during thermal treatment at a temperature of 1200 C. Microstructural observations reveal a uniform distribution of CS and Fe particles in the composite. Compressive strength and friction coefficient of obtained Fe/CS CM are in the range between 149-344 MPa and 0,15-1,1, respectively. Dependence of compressive strength on firing temperature is demonstrated exhibiting the maximum at 344 MPa. Dependence of coefficient of friction on a material properties, obtained at different firing temperature exhibits the minimum value of 0,15 at the firing temperature of 1150 C. The obtained syntactic form was shown to be a candidate for wear resistant applications

Metal-Coated Cenospheres Obtained via Magnetron Sputter Coating: A New Precursor for Syntactic Foams

Syntactic foams (SFs) and metal matrix syntactic foams (MMSFs) represent an advanced type of metal matrix composites (MMCs) based on hollow microspheres as particulate reinforcement. In general, SF and MMSFs allow tailoring of properties through choice of matrix, reinforcement, and volume fraction of the latter. A further handle for property adjustment is surface modification of the reinforcing particles. The present study introduces cenospheres for use as filler material in SF and MMSFs and as lightweight filler with electromagnetic interference shielding properties in civil engineering, which have been surface coated by means of physical vapor deposition, namely vibration-assisted sputter coating using a magnetron sputtering system. Altogether four types of such cenosphere-based composite powders (CPs) with an original particle size range of 50–125 µm (average particle size d50 75 µm) were studied. Surface films deposited on these were composed of Cu, stainless steel, Ti, and Ti-TiN double layers. For Cu coatings, the deposited metal film thickness was shown to be dependent on the sputtering energy. Scanning electron microscope backscattering images revealed nonporous films uniform in thickness directly after sputtering. Film thickness varied between 0.15 µm and 2.5 µm, depending on coating material and sputtering parameters. From these materials, samples were produced without addition of metal powders, exhibiting metal contents as low as 8–10 wt.% based on the coating alone. Obtained samples had an apparent density of 1.1–1.9 g/cm3 and compressive strengths ranging from 22 MPa to 135 MPa