China implements a floating exchange rate system after reforming the exchange rate mechanism in 2005. So far, nearly eight years, the RMB against the U.S. dollar increased from 8.2:1 to 6.1:1. Exchange rate risk of China's foreign contracted engineering industry has become a serious problem in the rapid development of the industry situation, this paper established exchange rate forecasting model base on the model of VaR through analysis the daily average exchange rate from July 22, 2005 to September 30, 2013, and estimate the rate of return by using the variance - covariance, historical simulation method, providing a theoretical basis for avoiding the exchange rate risk of China's foreign contracted projects.

The non-dendritic of A356 aluminum alloy billet was reheated to meet the requirements of the semi-solid microstructure by three different kinds of power, achieving the same final temperature of 863K. Subsequently, under the same conditions of die-casting (thixoforming), the microstructure was observed, surface hardness and tensile properties were measured. Afterwards, quantitative analysis was made for the microstructure of the reheated semi-solid of billet and the thixoforming parts. The results showed that the larger induction reheating power of the billet, the smaller the grain size of its microstructure and the higher surface hardness and the better mechanical properties of its thixoforming sample. Finally, through studying on the relationship between the microstructure of the semi-solid billet of A356 aluminum alloy and the mechanical properties of the thixoforming sample, we primarily achieved the reverse design of microstructure.