Dependence of effect on internal stresses in nickel: Experimental results by laser interferometry

Influence of internal stresses on field-dependent elastic modulus and damping in pure nickel

“…Thus, on the one hand, we can find in [8] estimations of elastic modulus between 190 and 210 GPa at demagnetized state and between 215 and 230 GPa at saturation state, these intervals being clearly in accordance with our results; on the other hand, in [7] we find results in even better agreement with ours, but our results provide a more detailed description of the trend of the curves with a thinner mesh of measured points. For the second magnitude studied, the specific damping capacity, we will refer only to [31], where magnetomechanical damping in pure nickel is studied (though for higher levels of stress), because [7], despite the fact that the same rods of nickel and similar heat treatments were used, does not provide results for damping. Thus, after extrapolating results below 1 MPa, [31] predicts values of damping for two specimens: one specimen ''cold rolled'', with values at demagnetized and saturated states of 0.30% and 0.07%, respectively, which fit our results for specimen ''AR''; and one ''annealed'' specimen, with values at demagnetized and saturated states around 25% and below 0.5%, respectively, which are very similar to our results for the specimens heated to 900 1C and slowly cooled in air or inside the furnace.…”

“…These values are in good agreement with other results in the literature. For the Young's modulus two main works can be used as reference: [8], which gathers measurements from many other researchers, and [7], which is specially convenient since it provides results for nickel specimens from the same molten material and manufacturing process as ours. Thus, on the one hand, we can find in [8] estimations of elastic modulus between 190 and 210 GPa at demagnetized state and between 215 and 230 GPa at saturation state, these intervals being clearly in accordance with our results; on the other hand, in [7] we find results in even better agreement with ours, but our results provide a more detailed description of the trend of the curves with a thinner mesh of measured points.…”

“…For the Young's modulus two main works can be used as reference: [8], which gathers measurements from many other researchers, and [7], which is specially convenient since it provides results for nickel specimens from the same molten material and manufacturing process as ours. Thus, on the one hand, we can find in [8] estimations of elastic modulus between 190 and 210 GPa at demagnetized state and between 215 and 230 GPa at saturation state, these intervals being clearly in accordance with our results; on the other hand, in [7] we find results in even better agreement with ours, but our results provide a more detailed description of the trend of the curves with a thinner mesh of measured points. For the second magnitude studied, the specific damping capacity, we will refer only to [31], where magnetomechanical damping in pure nickel is studied (though for higher levels of stress), because [7], despite the fact that the same rods of nickel and similar heat treatments were used, does not provide results for damping.…”

“…Regarding the disparity of results, previous studies have been carried out in nickel by Chicharro et al [7], but they only measured DEÀeffects and their results were less accurate, less extensive and less detailed. In this work we use a recently developed experimental system based on laser doppler vibrometry (LDV) which has proven its flair for estimating the variables with high accuracy, resolution and with the capability of including stress-dependence and path-dependence studies [12].…”

“…Furthermore, the fact that variations in the internal stresses of crystalline materials (and of amorphous materials also) may maximize their magnetoelastic behaviour has been widely proven [5][6][7]. In this work two salient magnetoelastic effects will be measured: the dependence of both elastic modulus and damping on the applied magnetic field, i.e., the so-called DEÀeffect, and magnetomechanical damping (or DCÀeffect for symmetry in nomenclature).…”