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Based on the comparison of traditional laser and fiber laser cutting system, a fiber laser based micro-machining system is designed. The main modules of the micro-machining system and the key techniques are analyzed and the corresponding solution is proposed. In particular, the driving, control and modulation system are focused on, in which an SOC system is built up, and the corresponding hardware and software are described in detail. The pulse width and frequency modulation are achieved with software, by setting the related parameters via keyboard. The power, pulse length and pulse frequency can be tunable in our modulation system, which can meet the different laser requirement in various kinds of stents cutting and micro-machining.

The effects of Re additions on the microstructure and phase stability of the cast fine-grain Mar-M247 superalloy were investigated in this study. The results showed that the grain sizes of the alloys with 0, 3, and 4.5 mass% Re content were 90, 60, and 50 mm, respectively. The primary 0 phase became finer and more cuboidal as Re content increased. The addition of 3 mass% Re caused strip-like MC carbides within the grain to degenerate into discontinuous M 23 C 6 carbides and initiated the formation of a deleterious topological closed-packed (TCP) phase within the grain interior. The addition of 4.5 mass% Re promoted phase instabilities that led to the precipitation of large amounts of needle-like P phase in the grain interior, attributable to Re and W segregation. This study found that 3 mass% Re was a critical addition to maintain optimal microstructure and phase stability, and improved the ultimate tensile strength and the yield strength at room temperature and 760 C. However, the addition of 4.5 mass% Re obviously resulted in a decrease in tensile properties at room temperature and 760 C.

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