Prof. Guohua Wu from the Institute of Light Alloys won the Innovation Research and Application Award of International Magnesium Science and Technology
Recently, Prof. Guohua Wu from the Institute of Light Alloys won the first Innovation Research and Application Award of International Magnesium Science & Technology. The award was founded by the International Magnesium Society and the Journal of Magnesium and Alloys. This honor is awarded to people or groups that have made major innovations in the research and industrialization of magnesium or magnesium alloys worldwide. It is voted by well-known international counterparts in the field of magnesium and magnesium alloys.
Under the leadership of Academician Wenjiang Ding, Director of the National Engineering Research Center of Light Alloy Net Forming, Prof. Wu has been engaged in the research and application development of high-performance magnesium rare-earth alloys, melt treatment, and liquid forming technology of magnesium alloys for a long time. Aiming at the problems of low strength, poor heat resistance, and low elongation of the existing cast magnesium alloys, the technical route of alloying by rare-earth elements (especially heavy rare-earth elements, such as Gd, Y, RE, etc.) was designed based on the solidification condition of slow cooling rate during sand casting. The addition process of RE elements, the generation laws of strengthening and heat-resistant phase, the microstructure, and the strengthening and heat resistance mechanisms were studied in detail. Two series of heat-resistant magnesium rare-earth cast alloys (Mg-Gd-Y and Mg-Y-RE alloys) with excellent comprehensive properties were developed by multi-element alloying and micro-alloying with employing the solution strengthening, grain refinement strengthening, and multi-stage aging strengthening. Aiming at the characteristics of magnesium alloys that are easy to oxidize and burn, and the removal of inclusions as well as the composition control of rare-earth elements are difficult, a model of accelerated transfer of inclusions in magnesium melt is proposed, and the dynamic loss mechanism of rare earth elements is revealed. Active rare earth compounds were first introduced into the flux, and a dedicated refining flux for magnesium rare-earth alloys was invented which can not only effectively remove the non-metallic inclusions in the melt but also realize the inhabitation of the loss of rare-earth elements. A MgO-based foam ceramic filter with a relatively large scale for magnesium alloy melt was invented to avoid the reaction between the traditional ceramic filters (such as Al2O3 and SiC) and high-temperature magnesium melt, thus a much higher removal rate of the flux inclusions in the melt was realized. The idea of integrating gas protection, flux purification, gas purification, and filtration purification was proposed, and a multi-stage and multi-media composite purification system for magnesium alloy melt was invented. In this way, the efficient removal of oxide inclusions and impurity elements, and the control of the burning loss rate of rare earth elements are realized, which greatly improves the purity of the magnesium melt. Based on the background of resin sand casting of aerospace components with large scale and complex shape, the effects of alloying composition, cooling rate, pouring temperature, and process parameters of the casting mold, etc. on the solidification behavior, solidification structure, and mechanical properties of sand-cast magnesium rare-earth alloys is revealed. The grain refinement mechanism of the high-strength heat-resistant magnesium rare-earth alloy under the slow cooling condition of sand casting is clarified. The relationship between the hot cracking tendency and the solidification behavior of magnesium rare-earth alloys was studied. The effects of the melt purification treatment, pouring temperature and alloying composition on the hot cracking tendency of the magnesium rare-earth alloy have been clarified. At the same time, the formation mechanism, the related inhabitation methods, and technical measures of the hot cracking in magnesium rare-earth alloy castings are proposed. The fabrication difficulties of magnesium alloy, such as the low purity of the alloy melt, easy oxidation and combustion, non-compact structure of castings, shrinkage cavity and porosity, and thermal cracking, were overcome by applying the invented heat-resistant magnesium rare-earth alloy with a series of corresponding processes and technologies. The application bottlenecks of poor surface quality, low dimensional accuracy, and heat treatment deformation have been overcome, and the low-pressure resin-sand casting technology of large-scale complex-shaped thin-walled magnesium alloy components with high strength and good heat resistance has been realized. A variety of key aerospace components have been developed and applied in new types of aircraft, engines, and aerospace vehicles, which have produced significant social value and high economic benefits. It can be concluded that Prof. Wu has made great contributions to promoting the development of magnesium alloys.
Prof. Wu was selected as a leading talent of Shanghai in 2019. He has presided over more than 50 scientific research projects such as the National Key Research & Development Program of China, the National Natural Science Foundation of China, the foundation enhancement project, and the aerospace special project. He has won 8 national and/or provincial awards of science and technology and published more than 180 SCI papers. Besides, Prof. Wu has participated in the compilation of 2 monographs and more than 50 invention patents have been authorized. Prof. Wu concurrently serves as the vice chairman of the China Magnesium Alloy Materials and Application Technology Professional Committee and the vice chairman of the China Foundry Society.