Decomposition Behavior of the &gamma;<SUB>Mn</SUB> Solid Solution in a Mn&ndash;20Cu&ndash;8Ni&ndash;2Fe (at%) Alloy Studied by a Magnetic Measurement

Remarkable Improvement of Damping Capacity of Mn–20Cu–5Ni–2Fe (at%) Alloy by Zinc Element Addition

“…From this, we can see that the damping capacity of alloy is proportional to the lattice distortion, and thus the larger the lattice distortion is, the better the damping capacity is. [11,23] According to the calculated a and c values of g 0 phase for two specimens in Table 2, the C Mn in nanoscale Mn-rich regions upon spinodal decomposition can be estimated for each specimen, as present in Table 3. Nanoscale Mn-rich and Cu-rich regions corresponding to typical tweed structure in TEM images can be created in Mn-Cu based damping alloys by spinodal decomposition after ageing at www.advancedsciencenews.com www.aem-journal.com 400-500 C for 4 h, [9,21,22] which also have been confirmed by TEM observation and EDX analysis in this work (the typical sweed structure and line-scan EDX results can be seen in Figure S1, Supporting Information).…”

“…[26] In this case, when Zn element is added to M2052, the absolute value of DG g!g0 will be increased due to the obvious reduction of items P X i G i g!g 0 , RT P X i ln X i , and DG E g!g 0 , eventually resulting in the enhancement of M s of alloy. It has been reported that when the C Mn is over 82% in Mn-Cu based alloys, Neel temperature (T N ) will be quite higher than M s , thus the contribution of magnetic phase transition to free energy can be negligible.…”

“…[6,7] The dissipation of vibrational energy by the movement of these boundaries under alternate stress makes this kind of alloy show high damping characteristics. [9][10][11] However, the higher Mn concentration would directly cause the alloy brittler, and other severe problems such as the lower elongation, impact toughness, and corrosion resistance. [8] Generally, the higher the Mn concentration in alloys is, the higher the martensitic transformation temperature (M s ) is, the more the f.c.t g' phase micro-twins as damping source obtained at room temperature (RT) is, thus the better the damping capacity is.…”

“…[9][10][11] However, the higher Mn concentration would directly cause the alloy brittler, and other severe problems such as the lower elongation, impact toughness, and corrosion resistance. [11,13] Even so, there are still some key problems that need to be solved further in order to gain better effect in practical applications, such as relatively low M s , insufficient martensitic transformation, and low service temperature. Therefore, in order to get both high damping capacity and good mechanical property simultaneously, Mn-Cu based alloys with Mn concentration of %70 at% are often used in many branches of industry, and in the meantime some alloying elements were added to further improve their overall performance.…”

The Damping Behavior of Ni Added Mn-Cu Damping Alloys

“…The misfitting at the (011) twin boundaries can be described by a rotation angle along [100] direction. 13) Therefore the rotation angle of the twin boundaries is decreased from 1.32 to 0.73 with the addition of Ni. Such twin boundaries with little interface strains may be easily moved under the application of external oscillating stresses.…”