The Damping Behavior of Ni Added Mn-Cu Damping Alloys

Abstract

The temperature and frequency dependent damping behavior of Ni added Mn-Cu alloys were investigated. Ni addition not only increased the magnitude of the phase-transformation damping peak, but also decreased its frequency dependence. A decreased transformation temperature was found in the Ni added Mn-Cu alloys under the same treating condition, which suggested a retarding effect of Ni on the decomposition of Mn phase during the slow-cooling process. The characteristic twin-boundary damping peak of Mn-Cu alloys was enlarged and broadened with the addition of Ni. According to the relaxation damping models the twin-boundaries in Ni added alloys had the larger activation energy, and also exhibited a broader distribution of relaxation time during the stress induced movement. In Ni added Mn-Cu alloys, the FCT Mn phase showed a larger axis ratio, c=a and the Cu-rich Mn phase coexisting with the FCT phase showed the similar lattice constants at ambient temperature. These microstructural features in Ni added Mn-Cu alloys might contribute to the improved damping behavior of the twin-boundary damping peak.

Mobility of Twin Boundaries in Fe-Pd-Based Ferromagnetic Shape Memory Alloys

“…This type of hysteretic behaviour is not different from that described by in terms of dislocation break away. 14,17) Cu-Al-Ni 18) , Ni-Mn-Cu 19) and Mn-Cu 20) show a relaxation peak related to the variants movement and in these cases the activation energy can be determined from the frequency dependence of the peak temperature. In contrast, in Ni 2 MnGa, where a relaxation peak related to variants movement could not be found, Gavriljuk et.…”

The Twinning Microstructure and Damping Behavior in Mn–30Cu (at%) Alloy

“…Meanwhile, according to the analysis in a previous work, 3) the width of the Gaussian distribution of relaxation time for the twin boundary damping is defined as, 2 ðÞ, and it is calculated with 2 ðÞ ¼ H shift =H profile . The width of relaxation time distribution shows a decreasing variation at the treating condition sequence from FC to AG5 and then AG20.…”

On the Internal Friction Due to the Twin Boundary-H Interaction in Martensite

“…Hasiguti and Iwasaki first reported a relaxation peak in B19' martensite in a Ti-Ni alloy in 1968 [6,7]. Later, similar peaks were also found in other shape memory alloys, such as Mn-Cu [8], Cu-Zn-Al-Ni [9] and Ti-Ni-Cu alloys [10]. Since the peak usually appeared around 200K when measured at low frequency, it was also called the "200K peak" in some literature.…”

“…Since the peak usually appeared around 200K when measured at low frequency, it was also called the "200K peak" in some literature. Many studies have been carried out to explore this relaxation peak over the past decades [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Several speculations were proposed to interpret the relaxation behavior.…”