WEAR PROPERTIES OF FE-CUC BASED MATERIALS PRODUCED BY POWDER METALURGY
In this study, Fe-Cu-C based compact in various weight ratios of iron, copper and graphite additions to starting powder have been produced by powder metallurgy. The effects of copper and graphite additions and sliding speeds during wear tests on wear behaviours were investigated. In this study, wear tests were carried out by using pin on disc sliding wear machine with the sliding speeds of 1, 1,5 and 2 msn at the constant loads of 20N. 2000 m total sliding distance was selected. Scanning Electron Microscopy (SEM) studies were carried out on the cross section of the compacts. Worn surfaces of the samples after tests were also examined by using scanning electron microscope and energy dispersive spectroscopy (EDS) analyses. The results obtained from experimental work shows that addition of copper and graphite and sliding speed effect on wear behaviours of sintered alloyed steel materials.
Influence of alloying element additions on tribological behaviour of sintered steels with high content in manganese-nickel
Abstract Manganese and nickel are alloying elements with a high hardenability. Manganese is an excellent substitute for nickel due to its low cost but presents a great affinity for oxygen. In this work, the friction and wear behaviour of sintered manganese–nickel steels, by a pin-on-disk test has been studied. The tests were made under dry conditions, 0.1 m/s and 10 N as linear speed and applied load, respectively. Wear behaviour was evaluated against spherical pin of martensitic stainless steel (49 HRC). High manganese–nickel sintered steels were manufactured with two levels of carbon: 0.3 and 0.7% by weight. The unique level of addition of pure electrolytic manganese and different prealloyed manganese–nickel (80Mn/20Ni, 55Mn/45Ni and 25Mn/75Ni) was 4% by weight. All the compositions were prepared by dry mixing in ball mill and compacted at 700 MPa using uniaxial pressing. The sintering was carried out at 1230 °C in 90N 2 /10H 2 as protective atmosphere. Density, porosity and hardness were evaluated. After sintering, all samples were polished at the same surface conditions and friction coefficients and wear rates have been measured. A complete microstructural study of the different steels and their transversal wear tracks was carried out. Deformations of ferritic areas, closed surface porosity and austenite–martensite transformation during wear test were detected. For materials with 0.7% C, the combined effect of carbon and manganese increases wear resistance.
Compressive and flexural properties of hemp fiber reinforced concrete
The compressive and flexural properties of hemp fiber reinforced concretes (FRC) were examined in this paper. Natural hemp fiber was mixed using dry and wet mixing methods to fabricate the FRC. Mechanical properties of the FRC were investigated. The main factors affecting compressive and flexural properties of the FRC materials were evaluated with an orthogonal test design. Fiber content by weight has the largest effect. The method for casting hemp FRC has been optimised. Under the optimum conditions, compressive strength increased by 4 %, flexural strength increased by 9 %, flexural toughness increased by 144 %, and flexural toughness index increased by 214 %.