Wedge waves (WWs) in wedges, including their dispersion characteristics and mode transformation, are investigated using the laser ultrasound technique. Pulsed laser excitation and optical deflection beam method for detection are used to record WWs. Numerous WWs are detected by scanning the excitation laser along the wedge tip. Dispersions of WWs are obtained by using the two-dimensional (2D) Fourier transformation method, and different WW orders are revealed on the wedges. Mode transformation is determined by fixing the distance between the excitation and detection position, as well as by scanning the samples along the normal direction of the wedge tip.
Laser-induced breakdown spectroscopy(LIBS)was developed to detect aluminumin nickel-based superalloys(K417,GH4033,DZ125L,(?)742y)using a non-intensified,non-gated,low-cost detection system.The precision of LIBS depends strongly on the experimental conditions.The calibration curves of A1(I)394.4 nm and A1(I)396.2 nm under the optimum experimentalparameters are presented.Finally the limit of detection(LOD)for aluminum is calculated fromthe experimental data,which is in the range of 0.09% to 0.1% by weight.
