Ti-based glassy alloy rods with diameters up to 5 mm were prepared for Ti 41:5 Zr 2:5 Hf 5 Cu 42:5 Ni 7:5 Si 1 in a mutli-component system of (Ti, Zr, Hf)-(Cu, Ni)-Si by conventional copper mold casting. The new multi-component glassy alloy exhibits moderate thermal stability with a supercooled liquid region (ÁT x ) above 50 K. The glass transition temperature (T g ), crystallization temperature (T x ), melting temperature (T m ), liquidus temperature (T l ), and the reduced glass transition temperature (T g =T l ) are 680 K, 730 K, 1143 K, 1199 K and 0.57, respectively. The cast glassy alloy exhibits compressive strength of 2080 MPa, tensile strength of 2040 MPa and Young's modulus of 100 GPa. The reason for the high glass-forming ability (GFA) of the Ti-based multi-component alloy is discussed on the basis of knowledge available for bulk glass formation.

A new ultrasonic propagation system has been constructed using macrofiber composite (MFC) actuators and fiber Bragg grating (FBG) sensors. The MFCs and FBGs can be integrated into composite laminates because of their small size and high fracture strain. The developed system can send and receive broadband Lamb waves. In this research, this system was used to detect delamination damage in composite laminates. First, the multiple modes of Lamb waves in a carbon-fiber-reinforced plastic (CFRP) quasi-isotropic laminate were identified by transmitting and receiving the symmetric and antisymmetric modes separately. Then, the mode conversions at both tips of a delamination were investigated through an experiment and a two-dimensional finite element analysis (FEA). A new delamination detection method was proposed on the basis of the mode conversions, and experiments were carried out on laminates with an artificial delamination. When antisymmetric modes were excited, the frequency dispersion of the received A 1 mode changed, depending on the delamination length owing to the mode conversion between the A 1 mode and the S 0 mode. This phenomenon was confirmed through the FEA and these results prove that this new method is effective in detecting a delamination in CFRP laminates.

New Ti-based bulk glassy alloys were synthesized in a multi-component alloy system of Ti-Cu-Ni-Al-Zr-Si-B. In a wide composition range of Ti > 50 at%, single-phase glass rods with diameters up to 2.5 mm were prepared using a conventional copper-mold casting method. The new Ti-based glassy alloys show compressive strength above 1900 MPa. The plastic (serrated) strain under compression is lager than 0.01. The new Ti-based glass phase exhibits relatively high thermal stability with a large supercooled liquid region (ÁT x ) above 50 K. These glassy alloys, however, exhibit complex crystallization behavior characterized by multiple exothermic-reaction peaks on their differential scanning calorimeter (DSC) curves. The glass-forming ability of this complex system is discussed on the basis of knowledge available for bulk glass formation.

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