ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The effects of applying different solution and ageing conditions on the electrical resistivity and precipitation behaviour of a Cu-1.3Ni-0.3Si-0.03P (wt%) alloy were studied. The electrical resistivity of solution-treated material is greatly reduced, by about 50%, by the ageing processes. The reduction in resistivity is due to depletion of solute atoms from the copper matrix by the formation of precipitates. Double ageing peaks appeared during isothermal ageing due to the formation of Ni3P and Ni2Si precipitates. The first maximum, due to the precipitation of Ni3P, appeared at about 1 h of ageing time, while the second peak, due to Ni2Si, appeared at around 10 h of ageing time when aged at 450°C. The precipitate Ni3P forms early and the alloy starts to over-age before Ni2Si precipitates and the alloy reaches maximum hardness. The maximum hardness produced by the precipitations of Ni3P and Ni2Si decreased with increasing ageing temperature from 450 to 550°C. The time to reach the maximum hardness due to Ni3P precipitation became shorter, while that of Ni2Si became longer, as the solution treatment temperature increased from 780 to 1020° C. The apparent activation energy for Ni2Si precipitation was found to be about 80 kJ mol−1 while that for Ni3P precipitation was about 25 kJ mol−1.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00553275
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