Advanced Materials and Processes Research Institute
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Influence of Some Material and Experimental Parameters on the Sliding Wear Behaviour of a Zinc-Based Alloy, Its Composite and a Bronze
No full textIn this investigation, an attempt has been made to analyze the sliding wear response of a zinc-based alloy reinforced with 10 wt.% SiC particles over a range of applied pressures (prior to seizure) at the sliding speeds of 1.26 and 2.52 m/s. The (zinc-based) matrix alloy was also characterised under identical test conditions to see the influence of the dispersoid (SiC) phase on the wear behaviour. The wear\ud
response of the (zinc-based) matrix alloy and composite was compared with that of a conventional bearing bronze. Wear rate increased with pressure. The slope of the wear rate versus pressure plots was low at low pressures which increased significantly at high pressures. This was the observation made in all the test conditions except in the case of the (zinc-based) matrix alloy tested at the\ud
higher speed; one slope only (similar to the one prior to seizure at the low speed) was noted in the latter case. The bronze attained best wear performance (i.e. minimum wear rate and maximum seizure pressure) irrespective of test conditions. Incorporation of dispersoid (SiC) particles improved the wear resistance (inverse of wear rate) and seizure pressure of the (zinc-based) matrix alloy. Frictional heating reduced in the case of the composite as compared to that of the matrix alloy. Further, presence of the reinforced (SiC) particles increased the seizure temperature of the matrix alloy while the seizure temperature was the maximum for the bronze. Wear response of the samples has been discussed in terms of specific characteristics of various microconstituents like thermal stability, load bearing and lubricating characteristics, and protection offered by the harder phase to the softer one. The wear behaviour has been substantiated through the characteristics of wear surfaces, subsurface regions and debris particles of the specimens
The Effect of Heat Treatment on Sliding Wear Behaviour of a Zinc-Based Alloy Containing Nickel and Silicon.
No full textLow-Stress Abrasive Wear Behaviour of a 0.2% C Steel: Influence of Microstructure and Test Parameters.
No full textLow stress abrasive wear behaviour of a 0.2% C steel: influence of microstructure and test parameters.
No full textA low (0.2%) carbon steel has been subjected to heat treatment to form varying quantities of ferrite plus martensite in its microstructure. This was achieved by holding the samples in the two-phase (ferrite plus austenite) region at three different temperatures (750, 780, and 810 °C) for a specific duration followed by quenching in ice water. In another exercise, the steel was also subjected to annealing treatment by austenitizing at 890 °C followed by furnace cooling for comparison purposes. The samples were subjected to low-stress (three-body) abrasion tests using an ASTM rubber wheel abrasion test apparatus at different wheel speeds (150, 273 and 400 rpm corresponding to linear speeds of 1.79, 3.26 and 4.78 m/s respectively) for different sliding distances at a fixed load of 49 N. Crushed silica sand particles of size ranging from 212 to 300 μm were used as the abrasive medium. The wear rate of samples decreased progressively with sliding distance until a (nearly) steady-state condition was attained. This was considered to be due to abrasion-induced work hardening of subsurface regions as well as the greater tendency of protrusion of the harder martensite/pearlite phase at longer sliding distances, thereby providing greater resistance to wear. Decreasing wear rate with increasing treatment temperature 750–810 °C could be attributed to the greater volume fraction of the hard martensite phase in the samples containing ferrite plus martensite. The lower wear rate observed in the case of the samples containing ferrite plus martensite over the annealed ones comprising ferrite and pearlite was attributed to the higher bulk hardness of the former. Increasing linear speed from 1.79 to 3.26 m/s led to an increase in wear rate. This could be attributed to greater tendency of the abrasive particles to create deeper scratches and scouping (digging). A reduction in wear rate with a further increase in the linear speed from 3.26 to 4.78 m/s could be due to a change in the mechanism of wear from predominantly sliding to rolling of the abrasive particles in view of the increased plastic deformability characteristics of the specimens due to higher frictional heating. The present investigation clearly suggests that it is possible to attain a desired combination of bulk hardness and microstructure (consisting of ferrite plus martensite) leading to optimum abrasion resistance in low-carbon steels. The quantity of the two phases in turn could be varied by suitably controlling the heat-treatment temperature
Studies on Kelsey jig treating Indian coal fines
No full textThe key operating parameters in a Kelsey jig have been identified based on the understanding of its operating principle. Empirical models have been developed to predict the performance of the Kelsey jig while treating typical Indian coal fines at a given operating condition. Empirical models developed have also been validated with some random experimental data generated within the range of the parameters studied
Sliding wear property of Al-Cu Based alloys with SiC particle reinforced Composites under varying Experimental Conditions
No full textThe article reports on the sliding wear behavior of SiC reinforced composites of Al-Cu alloy and its dependence and change with experimental parameters. Wear resistance in composites is mainly attributed to the effective resistance of the SiC particle to penetration, grinding and cutting by the ceramic particulates. When the particle sizes are small matrix strengthening of the particles as well as wear resistance of the particles contributes to improving the wear resistance. Under conditions where mild wear conditions prevail wear is generated by fracture and removal of the oxide layer which is formed in aluminum alloys as a result of continued sliding action
Analysis of thin film growth using finite element method.
Get PDFThe properties and the performance of epitaxial semiconductor thin films depend on the stress-state and the defect structure in\ud
the film. When the film is grown layer by layer, the accumulated elastic strain energy due to misfit strain between the substrate\ud
and the film is partially released by the formation of misfit dislocations at a threshold thickness. This investigation pertains to\ud
finite element analysis of the stress-state in epitaxial thin films as a function of the thickness and the release of the elastic energy\ud
by dislocation nucleation. To begin with, stress contours associated with the epitaxial growth and the nucleation of the dislocation\ud
are studied independently and the results are compared with the available analytical and experimental data. Subsequently, the\ud
above two are combined to analyze the effective potential energy state of the system. Essentially, the energy minimization process\ud
that involves accommodation of the misfit strains at a threshold film thickness is studied.\ud
� 2002 Elsevier Science B.V. All rights reserved
Studies on Bamboo Polymer Composites with Polyester Amide Polyol as interfacial Agent.
No full textThe effect of surface treatment on the properties of bamboo/epoxy, bamboo/polyester composites was investigated. An improvement in the properties was observed when the surfaces of the bamboo fibers were modified with polyesteramide polyol (PEAP). The performance of surface treated bamboo composites in terms of water resistance is significantly better than that of untreated bamboo composites. Polyester amide polyol treated bamboo composites exhibited better mechanical strength properties. Fractographic evidence such as fiber breakage/splitting and matrix adherence on the pulled-out fiber surface explains such behavior
