China
Africa
Explore chapters and articles related to this topic
Engineering Materials
Published in Leo Alting, Geoffrey Boothroyd, Manufacturing Engineering Processes, 2020
Leo Alting, Geoffrey Boothroyd
Copper alloys have a wide applicational spectrum, and a wide variety of alloys are commercially available. The most important copper alloys are brass, which is copper alloyed with 10–40% zinc, and bronze, which is copper alloyed with tin, aluminum, or nickel and correspondingly called tin bronze, aluminum bronze, and nickel bronze.
Properties and Uses
Published in Alan Cottrell, An Introduction to Metallurgy, 2019
Apart from strength and hardness, the advantage of the tin bronzes lies in their good corrosion resistance. The high cost of tin however has led in recent years to its substantial replacement by other metals such as aluminium, silicon and manganese. The effect of aluminium on strength and ductility is broadly similar to that of tin and aluminium bronzes are made with 4 to 7.5% Al, for working into strip, wire, rod and tube, and 7 to 9% Al for casting. The aluminium gives the alloy an excellent corrosion resistance and this, together with the fine golden colour achieved at about 7% Al, has led to the wide use of aluminium bronze for imitation gold jewellery and ornamental architecture. Because of its high strength and corrosion resistance, aluminium bronze is widely used for gears and other moving parts in machinery, condenser tubes and ships’ fittings. Silicon has broadly similar effects to those of aluminium, but its lower solubility restricts the amount added. A typical composition is 3% Si and 1% Mn. Silicon bronze is particularly suitable for welding because the silicon forms a protective silica flux. Manganese bronze is really a type of Muntz metal (40% Zn) containing a small amount of manganese, which acts as a deoxidizer and grain refiner, together with small amounts of tin, iron and aluminium for strength and corrosion resistance.
Resistance to Wear
Published in Harry J. Meigh, Cast and Wrought Aluminium Bronzes, 2018
Reversing or intermittent loading result in repeated stressing and un-stressing which give rise to fatigue. It is particularly prevalent in rolling contact as in ball bearings and gears and may also be caused by the hammering action of cavitation. Fatigue may in time lead to the formation of cracks at or below the surface and hence ultimately to spalling (chips or fragments of metal breaking off) and delamination wear. Aluminium bronze is reputed for its excellent fatigue resistant properties. Fatigue is greatly affected by surface conditions such as hardness and finish, by the structure of the alloy, by residual stresses and by freedom from internal defects. Generous fillets and fine finish reduce the high notch or stress- concentration factors that can lead to accelerated fatigue failure.159
Experimental investigations of electrochemical micromachining of nickel aluminum bronze alloy
Published in Materials and Manufacturing Processes, 2020
Sarangapani Palani, Poovazhagan Lakshmanan, Rajkumar Kaliyamurthy
Developments of products from new materials with superior properties have presented great challenges to the entire machining industry. Nickel aluminum bronze (NAB) alloy possesses high strength, high bearing capacity, good anti-seizing property, and superior corrosion resistant capabilities. It is one of the copper-based alloys designed for numerous engineering applications.[1–3] Copper (Cu) constitutes a major portion of NAB alloy followed by aluminum, nickel, and iron elements. Corrosion resistance property gets a significant improvement by the use of nickel element. Iron acts as a grain refining agent, which in turn improves the tensile strength of NAB alloy.[4]Typical applications of NAB alloy include marine water propellers, perforated orifice for biomedical/pharmaceutical industries, and pressure sensors.[5–7]
An overview of wire arc additive manufacturing (WAAM) in shipbuilding industry
Published in Ships and Offshore Structures, 2021
The copper and its alloys (see Table 3 for their grades) are mainly used in the shipbuilding industry for engine and boiler rooms due to its ability to resist corrosion by saltwater. The mechanical properties and corrosion resistance of the copper metal can be improved by using its alloys namely copper-nickel, bronze, brass and copper-beryllium. For marine applications, copper-nickel, and nickel-aluminium-bronze are used mostly since they offer improved macrofouling and anti-galling that are critical for uses in seawater (Power and Webster 2012; Shen et al. 2018a).
Assessing the Tribocorrosion Performance of Nickel–Aluminum Bronze in Different Aqueous Environments
Published in Tribology Transactions, 2019
Beibei Zhang, Jianzhang Wang, Hao Liu, Junya Yuan, Pengfei Jiang, Fengyuan Yan
The good combination of corrosion resistance and mechanical properties makes nickel–aluminum bronze (NAB) an excellent marine material, which is widely used for making ship propellers, pump shafts, valve stems, and fasteners (Wharton and Stokes (10); Lv, et al. (11); Neodo, et al. (12); Zhang, et al. (13)). NAB alloy is endowed with a good resistance to seawater corrosion by virtue of a thin protective layer, containing both copper and aluminum oxides (Wharton, et al. (14)). However, when the engineering components of NAB alloy are subjected to the impact of high-velocity fluid flow (cavitation), the impingement of solid particles (erosion) or the contact of solid parts (fretting or sliding) in corrosive environments, this oxide film can be damaged or completely removed, exposing the nascent metal to the surrounding environment. During this process, the environmental characteristics are important to determine the surface chemistry by interfering with the corrosion reactions. In turn, the oxidation or corrosion within wear track will alter the morphology of frictional surfaces, which has an impact on the friction and wear of materials (Wu, et al. (15); Zhang, et al. (16)). For example, Cui, et al. (17) reported that the lubricating effect of seawater was better than that of distilled water, so under the lubrication of seawater, Cu-6Sn-6Zn-3Pb alloy had a lower friction coefficient. However, the effect of seawater on the wear of metal is more significant because this corrosive solution will promote crack initiation and propagation on the material surface and ultimately lead to the formation of wear debris and accelerated material loss from the wear track. Furthermore, the applied potential is a factor relative to the surface chemistry conditions, given that the tribodeformation of materials depends on the electrochemical condition in the contact zone. The chemical–mechanical mechanism of tribocorrosion is not yet entirely understood, because it involves the surface characteristics of the sample and its antagonist, the mechanics of the tribological contact, and the environmental conditions (López, et al. (18); Wang, et al. (19); Eghlimi, et al. (20); Wang, et al. (21)). Therefore, it is significant to further investigate the synergistic phenomenon between wear and corrosion, including corrosion-induced wear and wear-induced corrosion.