Recently, there has been increasing demand for long life of industrial products. High-strength alloy coating on necessary parts can decrease manufacturing costs for prolongation of life. This study proposes a laser surface alloying method to form an Fe-Al alloy coat on carbon steel. A defocused CO₂ laser was used to irradiate Al foil on a steel block by shot lining. Mutual diffusion proceeds with laser heating of Al foil, and the Fe-Al alloy grows. For example, Fe₃Al grows at ≥950°C. Two laser irradiation methods were used. In low-speed laser scanning, the laser beam scanned along a straight line at 5.0 mm/s. In high-speed laser scanning, the laser beam was reciprocated along a straight line at 100 Hz, and was considered as a linear heat source. The metal structures of the laser-irradiated area were observed. The results indicated that a local Fe-Al alloy coat was formed by high-speed laser scanning without changing the properties of the base material.

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We propose a cutting method using a microcantilever with bonded an abrasive grain, and examine the behavior of the microcantilever during cutting. We obtain basic knowledge about the various vibration-assisted cutting using a microcantilever in cutting experiments. To observe the behavior of the microcantilever and achieve vibration-assisted cutting with a microcantilever, a measure of the "dynamic force curve" at the forced vibration state is proposed.

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Fine particle peening was examined about the effective factor to modification of metal microstructure as compared with conventional shot peening. Specifically, collision simulation was performed by the finite-element method based on the particle flight velocity measured with a high-speed camera. The influence of particle flight velocity on plastic deformation of the matrix in shot peening was examined. The results indicated that the plastic strain of the matrix on particle collision was not related to the size of particles, but showed an increasing tendency with increasing particle flight velocity. These observations indicated that the flight velocity of particles is an important factor governing plastic strain of the matrix. Moreover, the total plastic deformation energy around a plastic deformation range tended to increase with smaller particle size.

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