Effects of peening on magnetic‐flux density in a metallic glass

The change of the saturated magnetic‐flux density, Bs, with peening is studied for a Fe‐Ni‐Si‐B glass. The peened glass shows the large Bs. Taking the driving force of the peening to be the collision energy, a rate process theory is applied for the glass. The parameter of X [(Bs−B0s)/(Bms−B0s)] is used, where Bms and B0s are Bs of the peened glass at an extremely long period of time and the minimum value of Bs, respectively. Based on the rate process, X is expressed by the following equation: log10[−ln(1−X)]=n log10 t+log10 k. Bs approaches Bms with peening. Bms is 9.51 kG, when the correlation coefficient is maximum. The faster the cooling rate, the smaller the n and log k become. Thus, Bs can be obtained by controlling the cooling rate and peening time according to our discretion.