In recent years,the development of techniques for the controlled preparation of functional graded materials(FGMs)has become a vigorous research field.In this study,to improve the efficiency and accuracy of sample prep...In recent years,the development of techniques for the controlled preparation of functional graded materials(FGMs)has become a vigorous research field.In this study,to improve the efficiency and accuracy of sample preparations,an automated feeding system based on gravimetric principles for dry powder with three dosing feeders is designed and realized.The feeding rate and accuracy can be regulated by coordinating the protruded length L(mm)and rotational speed V(r/min)of the feeder stirrer.To demonstrate this automatic sample preparation system,the well-known thermoelectric material BixSb2-x-Te3(x=0.3,0.4,0.5,0.6,0.7 and 0.8)is selected and prepared by the developed system,and the composition distribution of the functional graded material is characterized.Experimental results show that the BixSb2_xTe3(x=0.3-0.8)functionally graded material crystalizes in the rhombohedral phase after hot-pressing sintering and annealing and the prepared sample has a good gradient composition distribution.This verifies the reliability and accuracy of the feeding system.The concept of samples with a gradient component and application of the automatic powder feeding system could considerably accelerate the research and development of new materials.展开更多
From 1980’s decade,the introduction of carbon composite materials in structural applications has been consistently increased in the successive generations of civil aircraft from Single Aisle to Middle-long Range to a...From 1980’s decade,the introduction of carbon composite materials in structural applications has been consistently increased in the successive generations of civil aircraft from Single Aisle to Middle-long Range to achieve a culminant point with more than 50%in structure weight in recent commercial civil aircraft.This evolution,done through successive iterations,has been possible by combining in the same time the improvement of intrinsic composite material performances and its transformation into prepreg production technologies together with the development of new manufacturing process for material lay-up automation at composite shop-floor manufacturer of aircraft composite parts.New challenges are still coming to continuously develop materials and technologies in order to pursue the production more cost-effective composite parts.Associated to higher aircraft production rate for single aisle,new challenges may force material and aircraft designers and producers to furthermore drive new products and processes introduction and new ways of transformation within in next decade of composite aircraft designs.We propose to illustrate these trends using past and recent developments and our return of experience from Hexcel on Civil Aircraft programs.展开更多
基金This work was supported by the National Key Research and Development Program of China(Grant No.2018YFB0703600)the National Natural Science Foundation of China(Grant Nos.51772186,91748116,61773254,61625304,and 61525305)+3 种基金in part by the Science and Technology Commission of the Shanghai Municipality(Grant Nos.16DZ2260601 and 16441909400)in part by the Shanghai Rising-Star Program(Grant No.17QA1401500)in part by the Shanghai Young Eastern Scholar Program(Grant Nos.QD2016029 and QD2016031)in part by the Shanghai Sailing Program(Grant No.17YF1406200).
文摘In recent years,the development of techniques for the controlled preparation of functional graded materials(FGMs)has become a vigorous research field.In this study,to improve the efficiency and accuracy of sample preparations,an automated feeding system based on gravimetric principles for dry powder with three dosing feeders is designed and realized.The feeding rate and accuracy can be regulated by coordinating the protruded length L(mm)and rotational speed V(r/min)of the feeder stirrer.To demonstrate this automatic sample preparation system,the well-known thermoelectric material BixSb2-x-Te3(x=0.3,0.4,0.5,0.6,0.7 and 0.8)is selected and prepared by the developed system,and the composition distribution of the functional graded material is characterized.Experimental results show that the BixSb2_xTe3(x=0.3-0.8)functionally graded material crystalizes in the rhombohedral phase after hot-pressing sintering and annealing and the prepared sample has a good gradient composition distribution.This verifies the reliability and accuracy of the feeding system.The concept of samples with a gradient component and application of the automatic powder feeding system could considerably accelerate the research and development of new materials.
文摘From 1980’s decade,the introduction of carbon composite materials in structural applications has been consistently increased in the successive generations of civil aircraft from Single Aisle to Middle-long Range to achieve a culminant point with more than 50%in structure weight in recent commercial civil aircraft.This evolution,done through successive iterations,has been possible by combining in the same time the improvement of intrinsic composite material performances and its transformation into prepreg production technologies together with the development of new manufacturing process for material lay-up automation at composite shop-floor manufacturer of aircraft composite parts.New challenges are still coming to continuously develop materials and technologies in order to pursue the production more cost-effective composite parts.Associated to higher aircraft production rate for single aisle,new challenges may force material and aircraft designers and producers to furthermore drive new products and processes introduction and new ways of transformation within in next decade of composite aircraft designs.We propose to illustrate these trends using past and recent developments and our return of experience from Hexcel on Civil Aircraft programs.
