共查询到20条相似文献,搜索用时 10 毫秒
1.
T. Satish Kumar R. Subramanian S. Shalini P. C. Angelo 《Forschung im Ingenieurwesen》2015,79(3-4):123-130
In the present study, the effect of reinforcement on microstructure, mechanical properties and corrosion behaviour of aluminium–silicon–magnesium (Al–Si–Mg) alloy matrix hybrid composites reinforced with varying amounts of zircon and alumina has been investigated. Hardness and room temperature compressive tests were performed on Al–Si–Mg alloy as well as composites. Hardness and compressive strength was found to be higher for composites containing 3.75?% ZrSiO4?+?11.25?% Al2O3. Similarly, Al–Si–Mg alloy and its composites were studied for corrosion behaviour in 1 N HCl corrosive media. The weight loss of all the composites was found to decrease with time due to the formation of passive oxide layer on the sample surface. The results obtained indicate that composites exhibit superior mechanical properties and corrosion resistance compared to unreinforced alloy. 相似文献
2.
AbstractBlown-powder laser surface alloying was performed on the magnesium alloy AZ91D with Al–Si alloy powder to improve corrosion resistance. Characterization by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD) analysis revealed that intermetallic compounds (IMCs) of Mg2Si, Al12Mg17 and Al3Mg2 were formed in the matrix of α-Mg and Al solid solutions in Al–Si alloyed layers. The anodic polarization test in 3.5% NaCl aqueous solution showed that preferential corrosion occurred in the α-Mg matrix of the AZ91D base metal. The Al–Si alloyed layers exhibited a lower corrosion rate and a higher polarization resistance than AZ91D. The compactly dispersed dendritic Mg2Si phase, and the dendritic and angular phases of Al12Mg17 and Al3Mg2 in the alloyed microstructure were observed to be corrosion-resistant, constituting a barrier that retards corrosion. Corrosion initiated at the interface between IMCs and the solid solution matrix, and at substructures of the matrix, subsequently pervaded into the surrounding microstructure. 相似文献
3.
Blown-powder laser surface alloying was performed on the magnesium alloy AZ91D with Al–Si alloy powder to improve corrosion resistance. Characterization by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD) analysis revealed that intermetallic compounds (IMCs) of Mg2Si, Al12Mg17 and Al3Mg2 were formed in the matrix of α-Mg and Al solid solutions in Al–Si alloyed layers. The anodic polarization test in 3.5% NaCl aqueous solution showed that preferential corrosion occurred in the α-Mg matrix of the AZ91D base metal. The Al–Si alloyed layers exhibited a lower corrosion rate and a higher polarization resistance than AZ91D. The compactly dispersed dendritic Mg2Si phase, and the dendritic and angular phases of Al12Mg17 and Al3Mg2 in the alloyed microstructure were observed to be corrosion-resistant, constituting a barrier that retards corrosion. Corrosion initiated at the interface between IMCs and the solid solution matrix, and at substructures of the matrix, subsequently pervaded into the surrounding microstructure. 相似文献
4.
《Materials Science & Technology》2013,29(11):1394-1402
Abstract6351 Al–Al4SiC4 composite has been developed through stir casting route by incorporation of fine TiC powder in 6351 Al melt. Simultaneous effects of the generation of in-situ particles (Al4SiC4 and Al3Ti) and grain refinement were observed. The in-situ generated Al4SiC4 particles were found to act as nucleation sites for primary α (causing grain refinement) along with engulfment effect promoting uniform particle distribution. As the volume fraction of Al4SiC4 particles increased, the dendritic solidification was suppressed (more equiaxed grains appeared) and overall grain size of the matrix decreased. Besides, the precipitation of Al3Ti occurred at the dislocation enriched region. Accordingly, hardness of the composite was improved with increasing content of Al4SiC4 particles. 相似文献
5.
Biplab Hazra Karuna Sindhu Ghosh Rajdeep Sarkar Supriya Bera 《Materials Science & Technology》2013,29(13):1632-1641
A novel short duration heat treatment schedule is proposed in the present investigation for the Al-17?wt-% Si-5?wt-% Cu alloy (AR alloy). The existing heat treatment uses long duration (4–24?h) holding at solutionising temperature prior to ageing treatment. In the present investigation, the AR alloy is subjected to isothermal holding at 590°C for 15?min followed by warm water quenching prior to the normal ageing schedule. Detailed microstructural investigations involving size and shape of primary as well as eutectic Si particles, porosity measurements along with hardness and tensile property characterisation are carried out to find the effect of isothermal heat treatment. The study reveals considerable improvement in microstructure and mechanical properties after this isothermal heat treatment. 相似文献
6.
《Materials Science & Technology》2013,29(8):1091-1096
AbstractThe influence of sliding interface temperature on friction and wear behaviour of eutectic (LM13) and hypereutectic (LM28) Al–Si base alloy in as cast and heat treated condition has been investigated. LM13 and LM28 alloys having nominal composition Al–12Si–1Ni–0.8Cu–0.6Mg and Al–17Si–1Ni–0.8Cu–0.6Mg used in this study. Wear and friction tests were performed under dry sliding conditions using a pin on disc type of friction and wear monitor with the data acquisition system conforming to ASTM G99 standard. It was found that sliding interface temperature has a close relation with wear and friction response of these alloys. Initial rise in temperature reduces the wear rate and as soon as a critical temperature (CT) is crossed, wear rate abruptly increases. The friction coefficient of both alloys first decreases with rise in temperature then subsequently increases beyond a certain temperature. The influence of temperature on wear behaviour in particular was found to be a function of alloy composition and heat treatment. For as cast LM28 alloy, the critical temperature (140°C) was found to be lower than that in the heat treated condition (180°C). A temperature–wear mechanism is proposed for these alloys. 相似文献
7.
《Materials Science & Technology》2013,29(11):1277-1282
AbstractA novel in situ reactive technique has been employed for preparing 2·0 wt-%TiB2/60Si–Al composite. The kinetic equations and the Arrhenius type equation were applied to compute the coarsening rate constant and the activation energy for grain growth for the composite when it was heated at semisolid state for partial remelting. Experimental results have shown that the in situ TiB2 particles can refine effectively the primary Si phase and restrain the Si phase growth. The cubic coarsening rate constant for the composite was computed to be in the range of 75–148 μm3 min?1 at temperatures in the range of 600–700°C, which was much less than that for the 60Si–Al alloy (1323–4523 μm3 min?1). The value of activation energy for grain growth for the composite was about twice of that for the 60Si–Al alloy. The composite exhibited a higher thermal stability than that of the 60Si–Al alloy, suggesting that the in situ TiB2 particles can effectively pin the grain boundaries and arrest the migration of liquid film in the semisolid state of the composite. 相似文献
8.
The microstructure and mechanical properties of Al–15%Mg2Si composite containing different Cr contents (0.5 wt.%–5 wt.%) were studied. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis were utilized to study the microstructures and fracture surfaces of the composite. The results revealed that the addition of Cr contents changes the size and morphology of both primary and eutectic Mg2Si phases. A new intermetallic compound (Al13Cr4Si4) was detected through the microstructural studies at higher Cr levels. Adding Cr also made significant raise in the hardness, ultimate tensile strength (UTS) and elongation values of the composite. A slight reduction in tensile properties was seen at high Cr concentrations (>2 wt.% Cr). The study of fracture surfaces of the Al–15%Mg2Si–2%Cr composite revealed the presence of less broken particles and more fine dimples. 相似文献
9.
Influence of retrogression and re-aging treatment on the microstructure, strength, exfoliation corrosion, inter-granular corrosion and stress corrosion cracking of an Al–Zn–Mg–Cu alloy has been investigated by means of optical microscope (OM), transmission electron microscope (TEM) and electrochemical impedance spectroscopy (EIS). The results show that retrogression and re-aging treatment can increase the size and the distribution discontinuity of the grain boundary precipitates, and lead to the increase of the corrosion resistance without the loss of strength and ductility. In addition, the analysis of electrochemical impedance spectroscopy shows that retrogression and re-aging treatment can enhance the resistance to exfoliation corrosion. 相似文献
10.
AbstractThe dynamic deformation characteristics and failure behaviour of laminated carbon fibre reinforced Al–Li metal matrix composite has been studied experimentally with the objective of investigating the dependence of mechanical properties on the applied strain rate and fibre volume fraction. A vacuum melting/casting process was used for manufacturing the tested composite. Impact testing was performed using a Saginomiya 100 metal forming machine and a compressive split Hopkinson bar over a strain rate range of 10-1 s-1 to 3×103 s-1. It is shown that the flow stress of the composite increases with strain rate and fibre volume fraction. The highest elongation to fracture values were found at low rate loading conditions, although a significant increase in ductility is obtained in the dynamic range. The composite appears to exhibit a lower rate of work hardening during dynamic deformation. Strain rate sensitivity and activation volume are strongly dependent on strain rate and fibre volume fraction. Fractographic analysis using scanning electron microscopy reveals that there is a distinct difference in the morphologies of the fractures, with corresponding different damage mechanisms, between specimens tested at low and high strain rates. Both strain rate and fibre volume fraction are important in controlling fibre fragment length and the density of the Al–Li debris. The relationships between mechanical response and fracture characteristics are also discussed. 相似文献
11.
《材料与设计》2015
High-pressure torsion (HPT) was used to produce hypoeutectic Al–7Si alloy samples having a range of microstructures to investigate the effect of the grain refinement on its corrosion behavior in 3.5 wt.% NaCl solution for the first time. Optical microscopy measurements reveal that with the HPT processing increased from 1/4 to 10 revolutions under an applied pressure of 6.0 GPa, brittle coarse silicon particles and intermetallic phases were effectively broken into ultrafine-grained particles and redistributed homogeneously into the Al-rich matrix. Open-circuit potential and polarization curves results exhibit that corrosion resistance of the Al–7Si alloy in NaCl solution was significantly enhanced upon high torsion strains, with corrosion rate reduced from 7.41 μm y−1 for the as-received sample to 1.68 μm y−1 for the 10-turn processed sample. Electrochemical impedance spectroscopy analysis combined with characterization of the corroded samples using scanning electron microscopy and energy dispersive X-ray spectroscopy indicates that the enhancement in corrosion performance of the Al–7Si alloy is due to the breakage of coarse silicon particles and intermetallic phases, the microstructure homogeneity and the increased HPT-induced active sites. It is demonstrated that microstructure refinement through HPT processing can significantly improve both microhardness and corrosion properties of the Al–7Si alloy. 相似文献
12.
《Materials Science & Technology》2013,29(4):446-450
AbstractThe fatigue behaviour of a cast Al–7Si–Mg alloy, conforming to A356, has been studied. Specimens of this material were tested in both the as cast condition and a solution treated and aged condition. It was observed that the size, number, and position of casting defects influenced the fatigue life very strongly. This marked effect nearly hides that of the heat treatment. Nevertheless, if the analysis is carried out considering only results obtained from sound specimens it is revealed that the heat treatment causes an improvement in the fatigue resistance of the alloy. 相似文献
13.
The microstructure, hot cracking susceptibility, and mechanical properties of a novel Al–Cu–Y alloy were investigated. The Al–4.7Cu–1.6Y alloy demonstrated very good casting properties, hot cracking susceptibility that is similar to Al–Si–Mg alloys. Analysis of the solidification process showed that the primary Al solidification is followed by the eutectic reaction Liquid→τ1(Al8Cu4Y)+Al and the peritectic reactions Liquid+τ6(Al,Cu)11Y3)→Al+τ1(Al8Cu4Y) (612°C) and Liquid+η(AlCu)→τ1(Al8Cu4Y)+θ(Al2Cu) (595°C). The τ1(Al8Cu4Y) eutectic phase demonstrated high thermal stability during homogenisation treatment. The recrystallisation temperature was in the range 250–350°C after rolling with previous quenching at 540 and 590°C and without heat treatment. The recommended annealing mode for material in the as-rolled condition is 100°C for 1?h: YS?=?273?MPa, UTS?=?305?MPa and El.?=?6.6%. 相似文献
14.
In order to develop a new high damping aluminium alloy with strength and toughness for advanced aircraft structure application, rapidly solidified (RS) Al–Fe–Mo–Si/Al alloys were synthesized. The damping behaviour, mechanical properties and microstructures of the alloys were studied. Results showed that the damping capacities of RS Al–Fe–Mo–Si/10–15% Al alloys are stable between 7.0–10.0×10-3 at room temperature, which almost reach the high damping threshold, 10.0×10-3. At lower frequency (0.1–10 Hz) the damping capacity is decidely frequency and temperture dependent above 50°C, with lowest frequency and highest temperature resulting in the highest less factor. It was noted that mechanical properties of the Al–Fe–Mo–Si/10–15% Al alloys are both excellent at room temperature (b=536–564 MPa, =7.2–11.4%) and at elevated temperature (250°C: b=295–324 MPa). Analysis of microstructures reveal that the damping capacity arises from deformation of the pure Al areas, and strength at elevated temperature from the dispersion strengthening of intermetallic phase. © 1998 Chapman & Hall 相似文献
15.
Shang Zhu Lizhen Yan Xiwu Li Shuhui Huang Hongwei Yan 《Materials Science & Technology》2019,35(10):1291-1300
This study investigates the effect of Zn addition two-step behaviour in an Al–Mg–Si–Cu alloy. During pre-aging at 100°C for 3?h, the Zn can partition into clusters because of the strong Zn–Mg interaction, prompting the formation of clusters. During subsequent artificial aging at 180°C for up to 240?min (peak hardness condition), the Zn does not significantly partition into clusters or precipitates, and the majority of Zn remains in the Al matrix. However, the presence of Zn in the matrix stimulates the transformation from clusters to GP zones to β′′ phases. The enhanced formation of GP zones and β′′ phases correlates well with the remarkable age-hardening response. 相似文献
16.
In this study, dry sliding wear behavior and corrosion resistance of Al–Cu–SiC–xNi (x: 0, 0.5, 1, 1.5 wt.%) composites were investigated. Effect of nickel content on the microstructure and hardness of the alloys was also studied. Wear tests were conducted using a ball on disc wear test device. Corrosion behavior of Al–Cu–SiC–xNi composite alloys in 3.5% NaCl solution was investigated by using potentiodynamic polarization, impedance spectroscopy and cronoamperometric methods. The results showed that the hardness of the composite alloy increases with increasing nickel content. Maximum wear resistance is reported with the addition of 1 wt.%Ni. It was determined that corrosion resistance of Al–Cu–SiC composite alloys improved with increasing nickel content in the alloy. 相似文献
17.
Nanocrystalline Al–Si alloy-based composites containing carbon nanotubes (CNTs) were produced by hot rolling ball-milled powders. During the milling process, the grain size was effectively reduced and the Si element was dissolved in the Al matrix. Furthermore, CNTs were gradually dispersed into the aluminum powders, providing an easy consolidation route using a thermo-mechanical process. The composite sheet containing 3 vol.% of CNTs shows ~520 MPa of yield strength with a 5% plastic elongation to failure. 相似文献
18.
Aboubakr Medjahed Mehdi Derradji Abdeldjalil Zegaoui Bingcheng Li 《Materials Science & Technology》2019,35(6):661-668
In this study, newly developed fibre-metal laminates (Al-LiFMLs) were prepared by a lay-up process of a high-performance surface-modified glass fibres/phthalonitrile (GFs/PN) composite and Al–Li alloy. The results showed that varying the composite considerably affected the tensile properties of the Al-LiFMLs, as well as exhibiting enhancements over the properties of both the individual Al–Li alloys and GFs/PN composite constituents. For instance, when the number of composite layers varied from 6 to 14, the ultimate tensile strength of the Al-LiFMLs increased from 315 to 611?MPa. It was revealed that the failure mode displayed a more ductile behaviour (up to 20%) for all the developed Al-LiFMLs affected by the ductile fracture mode of the Al–Li alloy. 相似文献
19.
Tiesong Lin Minxuan Yang Peng He Chao Huang Feng Pan Yudong Huang 《Materials & Design》2011,32(8-9):4553-4558
Carbon–carbon composite (C–C composite) and TiB whiskers reinforced Ti–6Al–4V composite (TiBw/Ti–6Al–4V composite) were brazed by Cu–Ni + TiB2 composite filler. TiB2 powders have reacted with Ti which diffused from TiBw/Ti–6Al–4V composite, leading to formation of TiB whiskers in the brazing layer. The effects of TiB2 addition, brazing temperature, and holding time on microstructure and shear strength of the brazed joints were investigated. The results indicate that in situ synthesized TiB whiskers uniformly distributed in the joints, which not only provided reinforcing effects, but also lowered residual thermal stress of the joints. As for each brazing temperature or holding time, the joint shear strength brazed with Cu–Ni alloy was lower than that of the joints brazed with Cu–Ni + TiB2 alloy powder. The maximum shear strengths of the joints brazed with Cu–Ni + TiB2 alloy powder was 18.5 MPa with the brazing temperature of 1223 K for 10 min, which was 56% higher than that of the joints brazed with Cu–Ni alloy powder. 相似文献
20.
《Materials Science & Technology》2013,29(10):991-994
AbstractThe effect of microadditions of Be and Ca on the aging behaviour of Al–0·75Mg–0·5Si alloy is investigated. It is shown that the addition of 0·1%Be significantly increases the hardening rate and the maximum hardness level attainable when the alloy is aged at various temperatures from room temperature to 300°C, while the addition of 0·2%Ca decreases both the hardening rate and the maximum hardness level attainable. Optical and scanning electron microscopical observations show a significantly higher precipitate density for the Be containing alloy and a slightly lower precipitate density for the Ca containing alloy when compared with the base Al–Mg–Si alloy. The results are consistent with an earlier kinetic study that indicated a Be enhanced nucleation rate for precipitation in the same alloy.MST/936 相似文献