Subsurface damage during dry sliding wear of Al-Al3Ni eutectic alloy (original) (raw)
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Some studies of wear of an Al-22wt.%Si alloy under dry sliding conditions
Wear, 1982
Aluminium-based alloys, which are considered useful for applications in which the strength-to-weight ratio is important, are also being studied for substitution as wear-resistant alloys [l] for cast iron components. Al-Si alloys have been used for tribological applications under conditions of both dry and lubricated contact. The wear behaviour of hypereutectic Al-Si alloys has been studied [2 -41 under various test conditions. It was observed [l] that, among several materials studied, a hypereutectic Al-Si alloy exhibited the lowest wear rate. Thus the hypereutectic Al-Si alloys have gained a definite status as wear-resistant materials. However, there have been conflicting
Effect of microstructure on the sliding wear performance of a Zn–Al–Ni alloy
Wear, 2000
Some observations pertaining to the sliding wear characteristics of a zinc-aluminium alloy containing nickel under varying material and test conditions have been reported in this investigation. Dry sliding wear tests were conducted on as-cast and heat-treated zinc-based alloy pins using a pin-on-disc machine. A steel disc was employed as the counterface. Sliding speeds adopted were 0.42, 2.68 and 4.60 mrs while the traversal distance was fixed at 500 m. Wear Ž tests were conducted at different pressures using separate pins in each case. Seizure pressure of the pins prior to traversing the sliding. distance of 500 m was determined at each speed. Wear rate and the extent of frictional heating increased with pressure and speed whereas seizure pressure practically followed a reverse trend. The wear rate versus pressure plot of the as-cast alloy pins assumed two slopes at the lowest speed wherein low slope Ž. indicating the occurrence of mild wear situation was noticed initially. This was followed by the attainment of a higher slope suggesting Ž. severe wear condition at increased pressures. At higher speeds, one slope only identical to the higher slope at the minimum speed was noted. Wear rate versus pressure plots of the heat-treated alloy pins followed a trend similar to the as-cast ones except that two slopes were noted up to the intermediate speed in the former case. Heat treatment changed the as-cast dendritic structure of the zinc-based alloy into the one with an improved uniformity of the Ž. distribution of various microconstituents, the nickel containing phase remaining practically unaffected. Softening of the as-cast alloy was also observed as a result of the heat treatment. However, in spite of reduced hardness, the heat-treated alloy pins attained improved Ž. wear behaviour i.e. reduced frictional heating and low wear rate over the as-cast ones irrespective of the test conditions. This was attributed to a more uniform distribution of microconstituents and reduced cracking tendency of the alloy as a result of the heat treatment. The alloy pins also attained better seizure pressure in heat-treated condition comparing with the as-cast ones at all the speeds except the maximum for the same reasons. A reversal in the trend at the maximum speed was thought to be due to the over-softening of the already Ž. Ž. softened heat-treated alloy pins under the influence of large frictional heat generated at the maximum speed. Under the circumstances, the heat-treated alloy pins tended to adhererfuse with the disc extensively while this tendency was relatively less for the as-cast ones in view of their higher hardness. Further, the extent of the negative influence of cracking tendency reduced allowing thermal stability to Ž. predominate the wear behaviour of the as-cast alloy pins in this case. The factor led to somewhat higher seizure pressure of the as-cast alloy pins at the maximum speed comparing with the heat-treated ones. Low wear rates correlated with less damage to the worn surfaces and to the regions below the worn surfaces and finer debris formation. Seizure led to severe damage to the worn surfaces and to the regions below the worn surfaces while the debris formed was quite bulky and coarser.
Influence of load and temperature on the dry sliding wear behavior of aluminium-Ni 3 Al composites
2011
The suitability of Ni3Al intermetallics as reinforcements for Al-base materials for tribological application has been investigated. For this purpose, an Al/Ni3Al (5 wt%, 10 wt% and 15 wt%) composite is prepared by powder metallurgy techniques and tested on a pin-on-ring apparatus. The effects of the applied load (83-150 N) and temperature (25-150°C) at a constant sliding velocity of 0.4 m/s on the wear behavior of Al-Ni3Al composites and wear mechanisms during dry sliding are investigated. The worn surfaces are examined by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). It is found that the wear resistance of Al-Ni3Al composites decreased with increasing load and with an increasing fraction of reinforcement Ni3Al particles. With an increasing fraction of Ni3Al particles, the wear resistance of the composites increased at higher test temperatures, but not at lower test temperatures, and generally with increasing test temperatures, the weight loss of compo...
Influence of Ti addition on wear properties of Al–Si eutectic alloys
Wear, 2001
The influence of Ti addition (up to 4 wt.%) on wear behavior of as-cast and heat-treated Al-12 wt.% Si eutectic alloy prepared by rapid cooling has been investigated in dry sliding against a steel counterface using a pin-on-disk apparatus. Worn surfaces and wear debris were examined and analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The addition of Ti to the binary Al-Si alloy led to the precipitation of Al 3 Ti phase. Among the Ti-containing alloys, the increase in Ti content improved wear resistance of both as-cast and heat-treated alloys. However, these alloys displayed higher wear rates, thus lower wear resistance, compared with the Al-Si binary alloy.
2012
The effect of grain refiner and modifier on the wear behaviour of Al–Si alloys has been investigated using a PinOn-Disc machine. Various parameters such as alloy composition, normal pressure, sliding speed and sliding distance were studied on Al–Si alloys. The cast master alloys (Al–Ti–B and Al–Sr) were then characterized by optical microscopic analysis. The results suggest that the wear resistance of Al–Si alloys increase with the addition of grain refiner and modifier as compared to the absence of grain refiner and or modifier. The present results also reveal an improvement in tribological properties, obtained due to the change in microstructure from coarse columnar dendrites to fine equiaxed dendrites and plate like eutectic Si to fine particles due to the addition of Al-Ti–B grain refiner and modifier (Sr), respectively. we are prepared samples for using both gravity-die and sand casting and also determine wear resistance for this sample and wear results compare with each other.
Dry sliding wear in binary Al-Si alloys at low bearing pressures
Journal of Materials Science Letters, 1992
The use of aluminium-based alloys as bearing materials has attracted the attention of designers in recent years. Among these, the A1-Si alloys were successfully used in automobile engine cylinder applications even as early as 1920. Subsequently there have been a number of investigations [1-6] to study the wear characteristics of these alloys under different conditions of testing. One of the most popular methods employed for simulated wear testing in the laboratory is the pin-on-disc machine with a continuously rotating disc, in which the effect of bearing pressure, sliding speed, alloy composition, the presence of interface films, etc., can be easily studied.
Progression of wear in the mild wear regime of an Al-18.5% Si (A390) alloy
Wear, 2006
The mild wear regime of a cast Al-18.5% Si (A390), a lightweight alloy used in automotive components requiring wear resistance, was investigated in order to characterize the progression of the sliding wear processes. Block-on-ring (SAE 52100 steel) type sliding wear tests were conducted under a controlled dry air environment with 5% relative humidity. It was observed that the mild wear regime consisted of two sub-regimes: The first sub-regime of mild wear (MW-1) occurred at loads between 0.2 N and 35 N, and the second sub-regime of mild wear (MW-2) between 60 N and 150 N. A common characteristic of MW-1 and MW-2 was the attainment of steady-state wear conditions. The load (L) dependence of the steady-state wear rates (W) in both sub-regimes was expressed as W = C(L) n , where C 1 = 1.08 × 10 −4 , n 1 = 0.56 for MW-1 and C 2 = 2.18 × 10 −4 , n 2 = 0.67 for MW-2. A transition regime, where the wear rates of MW-1 increased by 270%, occurred in the 35-60 N load range. The transition between MW-1 and MW-2 was accompanied by a rapid increase (25%) in the amount of material transferred to the counterface. Sliding wear in both sub-regimes proceeded by the formation of tribolayers that were initiated by iron transfer from the steel counterface to the silicon particles on the contact surfaces. Compared to MW-1, tribolayers were formed at a faster rate in MW-2 and the amount of material transferred to the counterface was larger. Also, in MW-2 the magnitudes of plastic strains (ε) in the deformed aluminum subsurfaces below the tribolayers were higher, e.g., at 40 m below the surface ε = 3 at 60 N, compared to ε = 0.1 at 10 N at the same depth. In addition, in MW-2, both the tribolayers and the material transferred to the counterface contained layers of aluminum, implying that the aluminum matrix became in contact with the counterface. Spallation of thick tribolayers formed in MW-2 as well as extrusion of exposed aluminum surfaces over the tribolayers were among the main reasons for the higher wear rates in this regime compared to MW-1.
Wear behavior of Al-Al3Ti composite manufactured by a centrifugal method
Metallurgical and Materials Transactions A, 1999
The purpose of the present study was to develop a wear-resistant, light Al-Al 3 Ti composite material. An Al-Al 3 Ti composite specimen was machined from a thick-walled tube of Al-Al 3 Ti functionally graded material (FGM) manufactured by the centrifugal method from a commercial ingot of Al-5 mass pct Ti master alloy. The alloy was heated to a temperature where solid Al 3 Ti particles resided in a liquid Al matrix, and then the centrifugal method was carried out. Al 3 Ti particles in a commercial alloy ingot exist as platelets, and this shape was maintained through the casting. Three kinds of wear specimens were prepared, taking into account the morphology of the Al 3 Ti particles in the thickwalled FGM tube; the Al 3 Ti particles were arranged with their platelet planes nearly normal to the radial direction as a result of the applied centrifugal force. The wear resistance of the Al-Al 3 Ti composite was significantly higher than that of pure Al. Wear-resistance anisotropy and dissolution of the Al 3 Ti into the Al matrix at the near-surface region, around 100 m in depth, were also observed. The mechanism of the supersaturated-layer formation and the origin of the anisotropic wear resistance are discussed. YOSHIMI WATANABE, Associate Professor, is with the Department the wear process. By using scanning electron microscopy of Functional Machinery and Mechanics, Shinshu University, Ueda 386with energy dispersive X-ray capability and X-ray diffrac-8567, Japan. NOBORU YAMANAKA, Associate Professor, is with the Department of Mechanical Engineering, Miyakonojo National College of tion, the microstructural features near the worn surface Technology, Miyakonojo 885-8567, Japan. YASUYOSHI FUKUI, Profeswere characterized. Based on experimental observations sor, is with the Department of Mechanical Engineering, Kagoshima Univerof microstructural changes near the worn surface, the wear sity, Kagoshima 890-0065, Japan.
The Influence of the Addition of 4.5 wt.% of Copper on Wear Properties of Al-12Si Eutectic Alloy
2015
The influence of 4.5 wt.% copper addition on wear behavior of as-cast Al-12Si alloy prepared by gravity casting is investigated in dry sliding against a steel counterface using a pin-on-disk apparatus. The microstructures of test alloys and worn surfaces were examined by scanning electron microscopy and energy dispersing X-ray spectroscopy. The addition of copper to the binary Al-12Si alloy led to the precipitation of CuAl2 phase. Copper addition resulted in a refinement of α-Al and a minor modification of eutectic Si. The Al-12Si-4.5Cu alloy showed a higher wear resistance as compared to Al-12Si binary eutectic alloy.