Influence of the dislocation structures on the magnetic and magnetomechanical properties of high-purity iron

Influence of Precipitate and Martensite Lath on the Magnetic Properties in Creep Damaged 11Cr-3.45W Steel

“…In general, the domain wall-dislocation interaction has been well known that the coercivity is proportional to the square root of dislocation density. [13][14][15][16] In this test result as shown in Fig. 1, the sharp decrease of dislocation density in the initial creep stage could be a strong influence on the coercivity, which is in good agreement with the previous studies.…”

Gradually Devitrified Co-Based Metallic Glass As a Model Material for Testing Néel's Theory of the Rayleigh Rule

“…Comparison of the experimental and calculated values of the parameter p is usually considered as a practical numerical test for the validity of the model used by Neel. However, the experimental values of this parameter, measured till now for numerous monoand poly-crystalline soft and hard magnets, are much larger than those expected from Néel's theory (see, e.g., [4][5][6]). For example, in the experiment performed by Porteseil [4] on Fe-Si single crystal rectangular frames, each containing a single active Bloch wall, the value of the parameter p was obtained as 260 which is more than two orders of magnitude larger than the expected value of 1.6.…”

Magnetic Hysteresis and Barkausen Noise in Plastically Deformed Steel Sheets

“…The distinction between the different deformation stages becomes blurred in polycrystalline materials, because the different orientations of the grains impose the activation of different slip planes since the inception of plastic straining, in order to preserve the mechanical coherence between neighbouring grains. Consequently, the work-hardening rate is the highest at low strains, as shown for interstitial-free (IF) steels [20] and ultra-low-carbon steels [21] of similarly small grain size (<s> = 17 μm and <s> = 16 μm, respectively), and for a very pure largegrained (<s> = 800 μm) Fe sample [22]. It is observed in fact (Figure 2a) that the work-hardening Δσ follows to good extent a square root dependence on plastic strain Δσ ∝ εp 1/2 , so that the coercive field, according to the previously introduced linear dependence Hc ∝ (τ−τ0) occurring along stages II and III in single Fe crystals, is expected to approximate the law Hc ∝ εp 1/2 .…”

“…Investigating such a phenomenology has obvious direct interest for steel sheets applied as magnetic cores of electrical devices, like transformers and motors, but it has also great appeal for the nondestructive assessment of the mechanical properties of the structural steels. It is remarkable that non-oriented and grain-oriented steel sheets can achieve their present-day excellent properties only through severe cold-rolling as large-grained (<s> = 800 µm) Fe sample [22]. It is observed in fact (Figure 2a) that the work-hardening ∆σ follows to good extent a square root dependence on plastic strain ∆σ ∝ ε p 1/2 , so that the coercive field, according to the previously introduced linear dependence H c ∝ (τ − τ 0 ) occurring along stages II and III in single Fe crystals, is expected to approximate the law H c ∝ ε p 1/2 .…”

“…Figure 3 shows that such a law approximately holds in the tensile strained fine-grained IF and ultra-low carbon steels, where different deformation stages cannot be recognized. The H c dependence on ε p in the large-grained extra-pure Fe sample is instead reminiscent of the response of the single crystal, with stage II following stage I above about ε p = 2% [22].…”