The Fe-rich alloys of Fe90-xSi5B5Mx (M= Cr or Mo; x=1, 2) are synthesized in the present study. The as-spun structure mainly consists of bcc phase plus a minor amount of metastable phase (Fe3B and/or Fe23B6). Comparing with the base alloy Fe90Si5B5, the corrosion resistance is improved significantly due to the formation of the passive film. Saturation magnetic flux density reaches 1.9 T for the melt-spun alloys Fe89Mo1Si5B5. The alloys present a nearly constant high permeability in a rather high magnetic field up to coercive field which can be used as a new kind of sensor material with good fundamental properties and low cost.

This paper reviews the features of alloy components, structure and mechanical properties, physical and chemical properties of metastable Al-based alloys developed by use of various liquid or vapor quenching-induced phases such as amorphous, quasicrystalline, nanocrystalline, nanocomposite, supersaturated solid solution and structure gradient phases. As advantages of the metastable Al-based alloys, one can exemplify a high tensile strength of 1500 MPa for amorphous alloys, high elevated temperature strength of 364 MPa at 573 K for nanoquasicrystalline alloys, high strength of 1000 MPa at room temperature and 520 MPa at 473 K for nanocrystalline alloys, relatively high strength of 596 MPa with large elongation of 16% for nanocomposite alloys and high strength of 900 MPa and distinct elongation of 5% for supersaturated fcc-Al solid solution. These highly functional properties, which have not been obtained for conventional crystalline Al-based alloys, have enabled the commercialization of metastable Al-based alloys as structural, machinery and sporting goods materials. Owing to the significant increase of various fundamental properties caused by the essential differences in the structures, the engineering importance of the metastable Al-based alloys is expected to increase steadily in the future low carbon and nature harmonious society.

A melt-spun Fe90Si5B5 alloy ribbon consists of bcc-Fe(Si) + Fe3B + amorphous phase and exhibits good bending ductility, high tensile fracture strength above 1000 MPa, high corrosion resistance and unique magnetic properties as exemplified for high saturation magnetization exceeding 1.9 T, moderately high initial permeability of about 150 and low coercivity of 745 A/m which are attractive for magnetic sensors utilizing a nearly constant high permeability with applied field up to coercivity. Besides, the tensile fracture strength and elongation increase significantly to 1286 MPa and 0.62%, respectively, after annealing for 900 s at 823 K. The Fe-Si-B alloy ribbons are attractive as a new type of sensor material with features of high bending ductility, high tensile strength and elongation, relatively good corrosion resistanceand unique soft magnetic properties with very high saturation magnetization.