Properties of Fe-Zr-N Thin Films
Gases emerging from Fe-Zr-N films with various compositions during heating were analyzed by thermal desorption spectroscopy. The structures and magnetic properties of films were also investigated. H2, N2 and Ar were detected at 300-400°C, 500°C and 650°C, respectively. Larger amounts of N2 were emitted by films which contained larger amounts of N2. The changes in composition of films due to the emerging N2 is as follows. The composition changed for N/Zr ratios ranging from N/Zr≫1 to N/Zr~1, but was unchanged when N/Zr1. A (100) preferred orientation occurred in films in which the composition was N~Zr≫8 at% in the as-deposited state, while either a (100) orientation or random orientation occurred in all other cases. Under the former conditions, Fe-Zr-N films showed excellent soft magnetic properties and thermal stability up to 700°C.
Fe-X-N(X=Zr, Hf, Nb, Ta)薄膜の磁気特性
To obtain ultra fine grains of α-Fe sputtered films of Fe-X-N (X=Zr, Hf, Nb, Ta), ternary systems in which each element X had strong affinity for nitrogen and ability of amorphous formation were prepared and the dependence of soft magnetic properties on composition of films was investigated. Good soft magnetic properties and high saturation flux density Bs were obtained in each system. In particular, Fe-Zr-N and Fe-Hf-N systems had a widespread soft magnetic region and exhibited zero magnetostriction and high Bs up to 16 kG at a certain composition.
Evaluation of buckling load and dynamic performance of steel shear wall retrofitted with strips made of shape memory alloy
One of the most imperfections of the steel shear wall is out of plane displacements that cause severe damage in both structural and non-structural elements. In this paper, the effects of shape-memory alloys on steel shear walls are investigated. First, a numerical analysis using the finite element method in ABAQUS software has been carried out according to an experimental test. The results of the numerical analysis have been verified with experimental results. Next, shape-memory alloy fibers have been added vertically and horizontally to various parts of the steel shear wall. The results show that retrofitting with the shape-memory alloy reduces the out-of-plane displacement of the steel shear wall under both cyclic and seismic loadings. Besides, the buckling load in the steel shear wall increases when it is retrofitted with the shape-memory alloy. Also, the total out-of-plane movement (accumulated absolute displacements) of the steel shear wall and non-structural damage are controlled by the characteristic of a shape-memory alloy material called “super-elastic”.