Quenched hysteresis

In contrast, the O diffusion constant drops to zero at 75 GPa (2.6 g/cc) for both L and S initial configurations. The surprisingly small hysteresis in the fluid to superionic transition allows us to place the transition point between 70 GPa (2.5 g/cc) and 77 GPa (2.6 g/cc). The small hysteresis is most likely caused by the weak O-H bonds at the conditions studied, which have free energy barriers to dissociation comparable with kBT (see below). Simulations that start from the L initial configurations are found to quench to an amorphous solid upon compression to 2.6 g/cc. 

Magnetically soft Fe-Ni alloys can have their properties altered by heat treatment. The compound NisFe undergoes an order-disorder transformation at about 500°C. Since the susceptibility of the ordered phase is only about half that of the disordered phase, a higher susceptibility is realized when the alloy is quenched from 600°C, a process that retains the high-temperature, disordered structure. Heat treatment of Fe-Ni alloys in a magnetic field further enhances their magnetic characteristics (see Figure 6.61), and the square hysteresis loop of 65 Permalloy so processed is desirable in many applications. A related alloy called Supermalloy (see Table 6.19) can have an initial susceptibility of approximately one million. 

Fig.2b shows that the temperature effect is much smaller than the hysteresis effect shown in Fig. 2a, at least in the range from 77 K to 125 K. The difference amounts to less than 0.1 mm at a pressure of 1.5 GPa and much less than 0.1 mm at a pressure of 0.7 GPa. For comparison quenching of VHDA from 125 K to 77 K at 1.5 GPa causes a change of -0.20 mm (cf. Fig. la) and quenching of HDA from 125 K to 77 K at 0.7 GPa causes a change of -0.17 mm (cf. Fig. 3a). That is, the thermal expansion of HDA and VHDA exceeds the thermal expansion of the apparatus and indium. Nevertheless, the temperature...

The fragmentation should involve dissipation, which is reflected in the hysteresis of the loading curves in Fig.. 5. Since the work done to the system is consumed to create the cluster, the cluster size is in the order of hundreds of nanometers. This value may reflect quenched heterogeneity of the first network of DN gels found in our study [30, 31]. 

Aging in glassy polymer films were also investigated in the frame of solvent induced glass transition [7] [8], Results are utterly different from those obtained with equivalent temperature cycles. Hysteresis at small activity as well as complex behavior of the melting time depending on the quench amplitude had been observed. This behavior was attributed to the possible coupled evolution of the free volmne and the solvent fraction. 

Fig. 38. Thermal variation of the resistivity for three PrHj specimens in the relaxed (open symbols) and quenched (solid symbols) state Ap, is the quenched-in p increase measured at 80 K and plotted as a function of in the inset. Note the hysteresis between 200 and 250 K. fori = 0.76 (Burger et al. 1988).

Fig. 47. Resistivity isotheimals at 0 K and at 295 K (or Fig. 46. Resistivity of HoHj , for various -values at in the case of M-S transitions) for HoHj. in the relaxed (R) and quenched (Q) state. Note the Note the diverging p for jc>0.13 (Daou and Vajda magnetic transitions below 10K (cf. flg. 66), the 1994). structural anomalies around 200 K (hysteresis ) and the M-S and S-M transitions for high x-values (Daou and Vajda 1994).

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