Journal of Alloys and Compounds, 2111212 (1994) 147-151 JALCOM 129 147 Internal friction and modulus defect in a-Fe-based, high-alloyed (Cr, zyxwvutsr MO) hidamets Igor S. Golovin Moscow State Aircraji Technology University,Petrovka 27, Moscow 103767 (Russian Federation) Abstract The influence of heat treatment on the internal friction (IF) and modulus defect (DM) of high chromium ferritic alloys and a-Fe has been examined. The mechanisms of formation of magnetoelastic and dislocation hysteresis have been investigated. Temperature ranges and critical points associated with different damping mechanisms have been established. 1. Introduction High chromium steels are of great interest due to their favourable combination of mechanical, corrosion and damping properties. Their position among other metallic materials is shown in Table 1, which combines information on the intrinsic damping capacity and the main mechanism of damping (!P= AW(A)/W(A) ==29rQ-l, where AW(A) is the dissipated and W(A) TABLE 1. Intrinsic damping capacity of some metals and alloys pgs IlE MAUI .ntmmmL LPMIYISI OF DAwlffi zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Heterogenity Movable zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA MWable Reversable Y0.l.X in structure domain walls dislocations martenslte t Tl-Bi alloy IsN(I Most of the medium-oarbn high-carbon low allo ed comnerclal steels* Alloys 4 the bese of Al (Al- &? ).I-1.0 Al-lO%Zn. Al-0.2%~1. Al-lOXS1, Al-5XCu). Tl alloys, &.c L Langltudlnal oscillation. the stored energy, A is the amplitude of deformation and Q-’ is the internal friction (IF); the damping index ?P0.1 is W at a=O.la 0.2, where a,,, is the yield stress. Good, stable mechanical properties and damping ca- pacity are necessary for use over a wide temperature range. 2. Experimental procedure Armco Fe and several b.c.c. alloys with a Cr content in the range 11-25 wt.% and MO content in the range O-6 wt.% were used. Measurements of the amplitude and temperature dependence of IF (ADIF and TDIF) and the modulus defect (DM) were made on wire specimens in the amplitude range 1 X lo-’ to 140 X 10m5, with a frequency of approximately 1 Hz and a magnetic field from zero to H, = 24 x lo3 A m-l, using an inverted torsion pendulum. An X-ray study was carried out using a DRON 2.0 apparatus. Small-angle scattering (SAS) of monochromatic neutrons (wavelength, 0.186 nm) was investigated using a neutron diffractometer “RAWAR”; tensile tests were performed using an “Instron” machine. Structural investigations were carried out using trans- mission electron microscopy: 3MB-100 with carbon re- plicas and JSM-7A with disc foils. 3. Experimental results Increasing the annealing temperature (I’,) of cold- worked wire specimens of a-Fe and Cr16 and Cr16Mo4 steels leads to a non-monotonic change in IF, shear modulus defect (Af21f2), magnetic susceptibility (x=B/ Z) and coercive force Hc (Fig. 1). The dislocation (Q,-’ at H,) and magnetomechanical (Q,-’ = Q-’ - Qd-‘) Elsevier Science S.A. SSDZ 0925-8388(94)00129-Z