Masakatsu Hinai1, Showhachi Sawaya1 and Hakaru Masumoto1
1The Research Institute of Electric and Magnetic Alloys, Yagiyama-Minami, Sendai
The internal friction Q-1, and magnetic and mecanical properties were investigated as a function of Cr concentration in Ni-Co-Nb-Cr alloys containing 25, 45 or 65%Co and 3 or 5%Nb when furnace-cooled or water-quenched after heating at 1273 K for 7.2 ks. Measurements of the Q-1 and magnetic properties were carried out by an inverted torsion pendulum method and an automatic recording fluxmeter, and the mechanical properties were studied by using an Instron-type tensile testing machtne.
The maximum internal friction against the maximum shear strain-amplitude, Qmax-1, increased with Cr concentration, and the highest values of 59--91×103 were obtained for the alloys investigated. In the case of Ni-Co-Nb-Cr alloys with constant 3%Nb and 25, 45 and 65%Co, the Qmax-1 were highest at 3%Cr upon furnace cooling and 1%Cr upon water quenching, respectively. In the case of Ni-Co-Nb-Cr alloys with constant 5%Nb and 25, 45 and 65%Co, the highest values of Qmax-1 were obtained at 1%, 3% and 2%Cr upon furnace cooling and at 1%Cr upon water quenching, respectively.
The coercive force Hc of the alloys decreased with the the increase in Cr concentration. The Hc of the alloys with high values of Qmax-1 increased with the increase in Co concentration; 0.051~0.053 kA/m at 25%Co, 0.075~0.11 kA/m at 45%Co and 0.10~0.13 kA/m at 65%Co.
Both the tensile strength and the yield strength of the alloys increased with increasing Cr concentration, while the elongation remained almost unchanged and showed fairly large values of 40~60%.
high damping alloy, damping capacity, internal friction, nickel-cobalt-niobium-chromium alloy, coercive force, tensile strength, yield strength, elongation
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