Formability of soft-magnetic Ni–Fe alloy sheet

The formabilities of Ni–Fe alloy sheets were evaluated by measuring their tensile strengths, yield strengths, elongations to failure, strain-hardening exponents, and plastic-strain anisotropy ratios R at various directions to the rolling direction and for various textures. The higher-nickel alloy (75–82Ni–12–18Fe–Mo–Cr–Cu/Mn) sheets had higher tensile strengths, elongations, and strain-hardening exponents than did those of the lower-nickel alloy (47Ni–53Fe). The strain levels of the forming-limit curves were higher for the higher-nickel alloys, as, generally, were the R-values obtained (0·67−0·93, compared with 0·38−1·1 for the lower-nickel alloys) and the R-value fluctuations. The R-value maxima at 45−67° to the rolling direction for the higher-nickel alloy sheets and the minimum at 45° for the lower-nickel alloy sheets are attributed to the competitive contributions of the {358}〈835〉 texture, which gives a maximum at 45°, and the {001}〈100〉 texture, which produces a minimum at 45°. Thus, the higher-nickel alloy sheets appeared, in general, to have superior formabilities to those of the lower-nickel alloy.