共查询到20条相似文献,搜索用时 15 毫秒
1.
Balamurali Krishnan Narayanan S Natarajan Muhammed Anaz Khan 《Materials and Manufacturing Processes》2017,32(14):1596-1605
A nickel-based superalloy was laser surface treated, and its erosion behavior was evaluated. The laser power and scan speed were varied in different levels to impart variations in microstructure and mechanical properties. The microstructure of specimens exhibited fine equiaxed grains to columnar structure at different parameters. A high cooling rate improved the hardness of the laser-treated specimen up to 603?HV0.3 compared to the base material hardness of 430?HV0.3. The rate of erosion increased linearly from 30° to 60° impingement angle and decreased at 75° impingement angle. The accumulation of the erodent inside the crater and the consequent absorbtion of the incident kinetic energy might have caused this reduction. The laser surface treated specimens exhibited ~1.5 factor of improvement in high temperature erosion resistance. This was attributed to the minimized energy transfer from impinging particle to the substrate achieved through laser surface melting. 相似文献
2.
Solid-particle erosion tests were carried out to study the effect of matrix material, impact angle, and impact velocity on
the erosion behavior of seven types of thermoplastic neat polymers (i.e., polyetherimide, polyetheretherketone, polyetherketone,
polyphenylene sulfide, polyethersulfone, polysulfone, and ultrahigh molecular weight polyethylene). Steady-state erosion rates
of these polymers have been evaluated at different impact angles (15–90°) and impact velocities (25–66 m/s). Silica sand of
particle size 200 ± 50 μm was used as the erodent. These polymers have exhibited maximum erosion rate (E
max) at 30° impact angle indicating ductile erosion behavior. Some of these polymers have shown an incubation behavior at lower
impact velocities for an impact angle of 90°. Correlations among steady-state erosion rate and mechanical properties and glass
transition temperature (T
g) were established. Morphology of eroded surfaces was examined using scanning electron microscopy and possible wear mechanisms
were discussed.
相似文献
A. P. HarshaEmail: |
3.
Aseptic loosening due to wear and dislocation of the implant represents the main complication after total hip arthroplasty.
To gain more insight into the influence of the implant position on wear, commercial alumina couplings have been tested in
a hip joint simulator under three different angles of cup inclination (23°, 45°, 63°) with respect to a horizontal plane.
The planned length of the test was ten million cycles. However, the test was stopped at 5.5 million cycles due to the fracture
of one of the femoral heads, tested with at angle of 63°. The residual stress state in the worn acetabular cups and in the
fractured femoral head were evaluated by the frequency shift and broadening of the R1 and R2 fluorescence bands due to the Cr3+ ions naturally present in alumina ceramics as trace impurities.
The gravimetric measurements did not show significant differences among the three different inclinations tested, in agreement
with previous simulator studies, but in disagreement with in vivo findings. The fluorescence measurements allowed to affirm that an angle of 63° represents a worsened mechanical condition
for the prosthetic component, with a consequently higher probability of fracture and/or damage potentially conducive to massive
wear. In the light of the fluorescence results, it did not appear surprising that the femoral head that fractured was the
one being tested at 63°. 相似文献
4.
《Advanced Powder Technology》2014,25(1):450-456
Y-doped ultrafine AlN powders were synthesized by a carbothermal reduction nitridation (CRN) route from precursors of Al2O3, C and Y2O3 prepared by a sol–gel low temperature combustion technology. The Y dopant reacted with alumina and thus forming yttrium aluminate of AlYO3, Al3Y5O12 and Al2Y4O9, which formed a liquid at about 1400 °C and promoted the transformation of Al2O3 to AlN and the growth of AlN particles. Compared with the conventional solid CRN process, Y dopant reduced the synthesis temperature by 150 °C, and Al2O3 transformed to AlN completely at 1450 °C. The content of Y dopant had little effect on the synthesis temperature of AlN whereas it influenced the phase of Y compounds in the products. As the Y/Al molar ratio was in the range of 0.007648–0.022944, the particle sizes of Y-doped AlN powders synthesized at 1450 °C were 150–300 nm. 相似文献
5.
《Composites Part B》2013,45(1):385-393
The aim of this study was to investigate the erosive wear behavior of glass fiber, CaCO3 particle and glass fiber/CaCO3 hybrid reinforced ABS/PA6 blend based composites. The samples were prepared by using melt mixing and injection molding techniques. The mechanical, thermal, morphological properties and erosive wear behavior were investigated in terms of reinforcing agent type and composition. It was observed that the tensile strength and modulus values of hybrid composites gave a value between tensile strength and modulus values of only fiber reinforced composites and only particle reinforced composites. From DSC analysis it was revealed that Tg and Tm of composites were not significantly affected by reinforcement; however, degree of crystallinity was found to be sensitive to reinforcement type and composition. The impingement angle was found to have a significant effect on the erosive wear behavior. The results indicated that composite materials exhibited maximum erosion rate at impact angle of 30° conforming their ductile erosion behavior. In order to investigate wear mechanisms, eroded surface analysis was done by scanning electron microscopy. Surface analysis showed that repeated impact of hard silica sand particles caused a local removal of the matrix from the fiber surface and led to form craters on the surface of the composite material. 相似文献
6.
This article investigates the 3D surface topography and 2D roughness profiles, and micrographs were analyzed in the abrasive water jet (AWJ) cutting of AISI D2 steel kerf wall cut surfaces by varying water jet pressures and jet impact angles. In 3D surface topography, roughness parameters such as Sq, Ssk, Sp, Sv, Sku, Sz, and Sa were improved by various jet impact angles with different water jet pressures. However, the roughness parameters Ssk and Sku strongly depend on the water jet pressure and jet impact angle. This is confirmed by kerf wall cut profile structures. Fine irregularities of peaks and valleys are found on the AWJ cut surfaces, as evident from 2D roughness profiles. The scanning electron microscope micrographs confirm the production of an upper zone not very much damaged and a lower striation free bottom zone, by using the jet impact angle of 70° with a water jet pressure of 200?MPa. Finally, the results indicate a jet impact angle of 70° maintaining the surface integrity of D2 steel better than normal jet impact angle of 90°. The results are useful in mating applications subjected to wear and friction. This has resulted in enhancement of the functionality of the AWJ machined D2 steel components. 相似文献
7.
8.
《Thin solid films》1987,147(2):153-165
Following previous work on the angular distribution of ejected particles, features of the oblique argon ion beam bombardment of fused silica were elucidated again but from a different aspect. Detailed observations were made of the erosion topographies of fused silica targets obliquely bombarded with partially neutralized argon ion beam at polar angles of 0°, 22.5°, 45° and 67.5° using scanning electron microscopy. The form of the erosion topography changed systematically from isolated circular etch pits at 0° to isolated crescent etch pits at 22.5° and continuous and homogeneous ripple structures at 45°. Scarcely any erosion pattern was found at 67.5°, except for rare band-like structures. Irrespective of the incidence angle of the beam these structures increased in size with total ion dose but their forms remained unchanged. Essentially the same phenomena were observed in the case of sintered SiO2-5wt.%P2O5 and SiO2-5wt.%B2O3 targets in spite of the fact that their surfaces were initially rougher than that of the fused silica target. 相似文献
9.
Silke Blindow Maxim Pulkin Dietmar Koch Georg Grathwohl Kurosch Rezwan 《Advanced Engineering Materials》2009,11(11):875-884
Freeze casting is a fabrication method that allows producing near‐net‐shaped ceramics with variable porosity. Hydroxyapatite (HA) was modified by the addition of different amounts of SiO2 nanoparticles during freeze cast preparation. The addition of SiO2 introduced a partial phase transformation of HA to β‐tricalcium phosphate and improved the form stability due to less shrinkage after sintering. The impact of surface roughness of pure HA ceramics and the influence of SiO2 introduction during freeze casting on adhesion, proliferation, and differentiation of human osteoblast‐like cells (MG‐63) was investigated. While both cell attachment and proliferation of smooth pressed HA was significantly enhanced compared to rough freeze cast HA, the addition of SiO2 improved the cell numbers of the latter. The expression of cell differentiation markers osteocalcin and collagen I was found to be supported by rough surfaces (Ra = 5–6 µm) in particular on ceramics containing SiO2 相似文献
10.
Ekaterini Chantziara Konstantinos Lentzaris Angeliki G. Lekatou Alexander E. Karantzalis 《Fatigue & Fracture of Engineering Materials & Structures》2019,42(7):1548-1562
In the present effort, aluminium matrix composites (AMCs) were produced by the addition of submicron‐sized WC particles of low (up to 2.5 vol%) content into a melt of Al1050. Casting was assisted by the use of K2TiF6 as a wetting agent and mechanical stirring in order to limit particle clustering. Particle distribution was reasonably uniform comprising both clusters and isolated particles. Various different reinforcing particles' phases were identified, both in situ (Al‐W, Al‐Ti, and Al‐W‐Ti intermetallic phases) and ex situ (WC particles) of various morphologies shapes and sizes. Increase of the reinforcing particle content led to an increase of the tendency for clustering. The wear properties of the composite were examined by dry sliding wear. The worn surfaces and the produced debris were examined by SEM‐EDX, and an effort to correlate the wear response of the produced materials with the matrix and the reinforcing phase characteristics was attempted. In general, the increase of the reinforcing phase content led to an improvement of the sliding wear response. Solid particle erosion experiments were carried out for impact angles of 30°, 60°, and 90°. Τhe eroded surfaces were examined with SEM‐EDX, and possible erosion mechanisms were proposed based on morphological and other material characteristics. Intensive particle clustering seemed to deteriorate the erosion resistance of the systems. Medium concentrations of the reinforcing particles (1.0‐1.5 vol% WC) are proposed as a recipe for optimum sliding wear and solid particle erosion resistance behavior. 相似文献
11.
TiAlN coatings were deposited on AA1050 and AA5083 aluminium alloys by high‐velocity oxy‐fuel (HVOF) spray process and evaluated for their mechanical and slurry erosion performance. In comparison to base alloys, the mechanical properties were found to enhance upon coating. The effect of working parameters namely impingement angle, impact velocity, erodent size and erodent feed rate on the slurry erosion wear rate has been investigated. The slurry erosion wear rate of the uncoated samples was found to decrease with an increase in the impingement angle whereas for coated samples the slurry erosion wear rate first increased, reached to a maximum value at 60° and then decreased with further increase in the impingement angle. For uncoated and coated samples the slurry erosion wear rate was found to increase with an increase in impact velocity, erodent size and erodent feed rate. Finally, the morphology of the eroded surfaces was analyzed using scanning electron microscopy and the possible erosion mechanisms have been studied. 相似文献
12.
Mullite-bonded porous silicon carbide ceramics were prepared by an in situ reaction bonding technique and sintering in air with SiC, porous Al2O3, and graphite as starting materials. The pores in the ceramics were formed by burning graphite and by stacking particles of SiC and Al2O3. The surface of SiC was oxidized to SiO2 at high temperature. With a further increase in temperature, SiO2 reacted with Al2O3 to form mullite. The reaction-bonding characteristics, phase composition, open porosity, mechanical strength as well as the microstructure of porous SiC ceramics were investigated. 相似文献
13.
Yukio Saito Kouji Sato Shinpei Matuda Hideomi Koinuma 《Journal of Materials Science》1991,26(9):2441-2444
Diamond synthesis from CO-H2 plasma has been carried out on various substrate materials, e.g. metals: nickel, cobalt, tungsten, molybdenum, copper and ceramics: SiC, SiO2, Al2O3, ZrO2, AlN. Diamond formation was confirmed on every substrate with the exception of cobalt and nickel. The highest density of diamond nucleation, over 108 cm–2, was obtained on amorphous SiO2, the carbide-forming metals tungsten and molybdenum and on SiC; on these the nucleation density was one order of magnitude higher than on the other substrates. Diamond films prepared on tungsten, molybdenum and SiC substrates had a strong adhesion force: 1.3 to 1.5 kg mm–2. 相似文献
14.
Process and wear behavior of monolithic SiC and short carbon fiber-SiC matrix composite 总被引:1,自引:0,他引:1
The process and wear behavior of monolithic SiC and 10 vol. % short carbon fiber-SiC matrix (C-SiC) composite have been studied. The results indicate that, among ethyl alcohol, acetone, n-hexane and n-octyl alcohol, n-octyl alcohol was the most effective dispersing agent in dispersing both SiC powder and short carbon fiber. Among AlN, Al2O3, B4C, graphite, AlN/B4C, AlN/graphite, B4C/graphite and Al2O3/B4C, the most effective sintering aid for the fabrication of SiC and C-SiC composite was a mixture of 2 wt% AlN and 0.5 wt% graphite. The monolithic SiC hot-pressed at 2100°C exhibited higher density but lower flexural strength than those hot-pressed at 2000°C due to a grain growth effect. For the C-SiC composite, both density and strength of the composite hot-pressed at 2100°C were generally higher than those hot-pressed at 2000°C. The density and strength of C-SiC composite were lower than those of monolithic SiC under the same hot pressing conditions due to a higher porosity level in the composite. When monolithic SiC slid against C-SiC composite, the weight losses of SiC and the composite were each less than that of self-mated SiC or self-mated C-SiC. In the self-mated SiC tribosystem, a mechanically stable film could not be established, resulting in an essentially constant wear rate. When sliding against C-SiC, a thin, smooth and adherent debris film was quickly formed on the SiC surface, resulting in a lower wear. 相似文献
15.
Taner Yilmaz 《Journal of Materials Science》2010,45(9):2381-2389
The influence of annealing duration on the erosive wear behavior of short glass fiber (40% w/w) and CaCO3 mineral particulate (25% w/w)–short glass fiber (40% w/w) (total: 65% w/w) reinforced PPS composites has been characterized
under various experimental conditions by differential scanning calorimetry (DSC) and erosion measurements. The erosive wear
of the composites have been evaluated at different impingement angles (30, 45, 60, and 90°) and at four different annealing
periods (30, 60, 90, and 120 min). Increase in the total crystallization causes an improvement in the erosive wear properties
of the samples. Annealing time controls the morphology by influencing the degree of crystallinity in the matrix and in the
fiber–matrix interface. This formation restricts fiber–matrix debonding. There is no linear proportionality between annealing
time and relative degree of crystallization. The results indicate that PPS composites show maximum in wear versus impact angle
relation at 60° confirming their semi-ductile failure behavior. The morphologies of eroded surface are examined by the scanning
electron microscope. 相似文献
16.
In this study, the cathodic arc evaporation technique, by using the chromium target and controlling the flow rate of nitrogen/oxygen reactive gases, was utilized to deposit three different Cr-N-O coatings (CrN, CrN/Cr(N,O), CrN/Cr2O3) on AISI M2 tool steel. Two types of wear tests were applied to evaluate the abrasive and erosive wear behavior of the coated and uncoated specimens. One was the ball-on-disk abrasion test to measure the friction coefficient of these specimens. The other was the erosion test using Al2O3 particles (~ 177 µm in size and Mohr 7 scale) of about 5 g, and then the surface morphologies of the eroded specimens were observed. To further understand the coating effects on the two wear behaviors of M2 steel, coating structure, morphology, and adhesion were analyzed using XRD, SEM, and TEM, respectively. The results showed that surface roughness and adhesion of the double-layered coatings (CrN/Cr(N,O) and CrN/Cr2O3) were inferior to those of monolithic CrN, but their hardness and elastic modulus were superior to those of CrN. In the abrasive behavior, Cr-N-O coatings reduced the friction coefficient of M2 substrate. In particular, the CrN/Cr2O3 has the highest hardness/elastic (H/E) modulus ration, therefore the lowest friction coefficient, among all the coated-specimens tested. In the erosive behavior, the coated specimens exhibited better erosion resistance as compared to the uncoated ones, at the impingement angles of either 30o or 90o. Moreover, the erosion resistance of CrN/Cr(N,O) coatings was superior to that of CrN/Cr2O3 coatings due to its better adhesion. 相似文献
17.
M. K. Guseinov M. K. Kurbanov G. K. Safaraliev B. A. Bilalov 《Technical Physics Letters》2005,31(2):138-139
Magnetron sputtering of polycrystalline SiC-AlN targets was used to obtain films of (SiC)1− x
(AlN)x solid solutions on silicon carbide (6H-SiC) substrates heated to a temperature in the range T = 500–1200°C. The deposits were characterized with respect to structure, composition, and optical absorption. It is demonstrated
that the films obtained on 6H-SiC substrates at T ≥ 1000°C possess a single crystal structure. The compositions of (SiC)1−x
(AlN)x films are close to those of the corresponding SiC-AlN targets. 相似文献
18.
Xiumin Yao Shouhong Tan Xiangyu Zhang Zhengren Huang Dongliang Jiang 《Journal of Materials Science》2007,42(13):4960-4966
SiC reticulated porous ceramics (SiC RPCs) was fabricated with polymer replicas method by using MgO–Al2O3–SiO2 additives as sintering aids at 1,000∼1,450 °C. The MgO–Al2O3–SiO2 additives were from alumina, kaolin and Talc powders. By employing various experimental techniques, zeta potential, viscosity
and rheological measurements, the dispersion of mixed powders (SiC, Al2O3, talc and kaolin) in aqueous media using silica sol as a binder was studied. The pH value of the optimum dispersion was found
to be around pH 10 for the mixtures. The optimum condition of the slurry suitable for impregnating the polymeric sponge was
obtained. At the same time, the influence of the sintering temperature and holding time on the properties of SiC RPCs was
investigated. According to the properties of SiC RPCs, the optimal sintering temperature was chosen at 1,300 °C, which was
lower than that with Al2O3–SiO2 additives as sintering aids. 相似文献
19.
Materials resistant to high temperature corrosion and small particle impact erosion are necessary in the design and construction of energy conversion systems. Al2O3-forming M-Cr-Al coatings with active element additions on an IN 738 substrate have exhibited enhanced resistance to erosion damage of their oxide scales owing to improved adherence of the scale. This improvement results from modifications of the scale morphology by the active element additions which encourage pegs of oxide that penetrate into the coating. Other active element additions cause a porous scale to form, increasing the erosion susceptibility. The thin alumina scales behave as a brittle material with the highest erosion rate occurring at an impingement angle of 90° and scale removal occurring by a chipping action. 相似文献
20.
Interaction between silicon carbide and a nickel-based superalloy at elevated temperatures 总被引:3,自引:0,他引:3
A study has been made of the reaction of hot-pressed SiC and a nickel-based superalloy at temperatures between 700 and 1150°
C. Under conditions of reduced oxygen pressure at the reaction interface, obtained by applying pressure to the couple, some
degree of reaction was observed in both metal and ceramic at all temperatures studied. Preliminary studies utilizing the same
techniques at 1000° C with a Si-SiC ceramic composite, Si3N4, MgO, Al2O3, and SiO2 also indicated some degree of reaction in the metal for all ceramics examined. 相似文献