高熵合金只有15年的研究历史,由于具有独特的成分设计、简单的微观结构、优异的性能而受到广泛关注。根据元素的选取不同,高熵合金也被划分为3d过渡金属元素高熵合金、难熔高熵合金、镧系过渡金属元素高熵合金以及轻质高熵合金等。其中...高熵合金只有15年的研究历史,由于具有独特的成分设计、简单的微观结构、优异的性能而受到广泛关注。根据元素的选取不同,高熵合金也被划分为3d过渡金属元素高熵合金、难熔高熵合金、镧系过渡金属元素高熵合金以及轻质高熵合金等。其中,轻质高熵合金在2010年之后才进入人们的视野,其组成元素大多为轻金属,在具备高强度、高硬度、耐磨损、耐腐蚀等优异性能的同时,还具备密度小的优点,可用于航空航天、新能源汽车、军事工业等领域,具有远大的发展前景。然而,制约轻质高熵合金发展的因素也很多,主要为理论机制的不完善、制备工艺的不成熟以及生产成本高昂。理论机制不完善主要体现在高熵合金的相结构难以预测以及四大效应不能完全解释高熵合金微观结构和性能的独特性;制备工艺的不成熟主要体现在块体轻质高熵金的制备方式较少且不利于大批量工业生产;成本高昂主要体现在大多数轻金属单质价格昂贵且每种元素在轻质高熵合金中的成分占比较高。由于发展历程较短,上述问题还不能得到有效解决,目前对轻质高熵合金的研究集中在:根据现有的理论及生产水平,设计密度低、力学性能优异的新型合金。目前,成功开发出的轻质高熵合金有Al 20 Li 20 Mg 10 Sc 20 Ti 30、Al 20 Be 20 Fe 10 Si 15 Ti 35以及AlLiMgZnSn等,这些合金分别采用机械合金化法、电弧熔炼法以及感应熔炼法进行制备,拥有低密度、高强度的优点,这些制备工艺为今后的研究提供指导。本文归纳了轻质高熵合金的研究进展,分别对轻质高熵合金的四大效应、设计原则、制备工艺、微观结构和力学性能进行了介绍,分析了现阶段轻质高熵合金研究的不足之处并对轻质高熵合金未来在生产生活中的应用进行了展望。展开更多
In this study, the soft magnetic properties and crystallization behavior of Fes3B10C6-xSixCul （x=0-4） nanocrystalline alloys prepared by annealing the melt-spun amorphous ribbons have been investigated. It is found ...In this study, the soft magnetic properties and crystallization behavior of Fes3B10C6-xSixCul （x=0-4） nanocrystalline alloys prepared by annealing the melt-spun amorphous ribbons have been investigated. It is found that in the Fe83B10C6-xSixCU1 alloy system, the coercivity （Hc） decreases slightly with increasing Si addition and exhibits a minimum value with composition of x = 2, while the effective permeability （Ue） shows an opposite variation trend. The saturation magnetic flux density （Bs） shows a slightly decreasing trend owing to the decreasing volume fraction of nanocrystalline phase. The Fe83B10CaSi2Cu1 nanocrystalline alloy exhibits excellent soft magnetic properties with a high Bs of 1.78 T, high ue of 13 600 and low Hc of 4 A/m.展开更多
In this paper,an InGaN metal-insulator-semiconductor(MIS) photodetector with an ultra-thin Al2O3 insulation layer deposited by atomic layer deposition(ALD) was studied.A high photoelectric responsivity of 0.25 A/W and...In this paper,an InGaN metal-insulator-semiconductor(MIS) photodetector with an ultra-thin Al2O3 insulation layer deposited by atomic layer deposition(ALD) was studied.A high photoelectric responsivity of 0.25 A/W and a spectral responsivity rejection ratio of about three orders of magnitude at 1 V reverse bias were achieved for this MIS photodetector.The dominant carrier transport mechanism in the InGaN MIS photodetectors is submitted to the space charge limited current(SCLC) mechanism at high field and exhibits an Ohmic-like conduction at low electric field.The results indicate that the ultra-thin Al2O3 film deposited by the ALD technique can act as an excellent insulation dielectric for the InGaN photodetectors.展开更多
文摘高熵合金只有15年的研究历史,由于具有独特的成分设计、简单的微观结构、优异的性能而受到广泛关注。根据元素的选取不同,高熵合金也被划分为3d过渡金属元素高熵合金、难熔高熵合金、镧系过渡金属元素高熵合金以及轻质高熵合金等。其中,轻质高熵合金在2010年之后才进入人们的视野,其组成元素大多为轻金属,在具备高强度、高硬度、耐磨损、耐腐蚀等优异性能的同时,还具备密度小的优点,可用于航空航天、新能源汽车、军事工业等领域,具有远大的发展前景。然而,制约轻质高熵合金发展的因素也很多,主要为理论机制的不完善、制备工艺的不成熟以及生产成本高昂。理论机制不完善主要体现在高熵合金的相结构难以预测以及四大效应不能完全解释高熵合金微观结构和性能的独特性;制备工艺的不成熟主要体现在块体轻质高熵金的制备方式较少且不利于大批量工业生产;成本高昂主要体现在大多数轻金属单质价格昂贵且每种元素在轻质高熵合金中的成分占比较高。由于发展历程较短,上述问题还不能得到有效解决,目前对轻质高熵合金的研究集中在:根据现有的理论及生产水平,设计密度低、力学性能优异的新型合金。目前,成功开发出的轻质高熵合金有Al 20 Li 20 Mg 10 Sc 20 Ti 30、Al 20 Be 20 Fe 10 Si 15 Ti 35以及AlLiMgZnSn等,这些合金分别采用机械合金化法、电弧熔炼法以及感应熔炼法进行制备,拥有低密度、高强度的优点,这些制备工艺为今后的研究提供指导。本文归纳了轻质高熵合金的研究进展,分别对轻质高熵合金的四大效应、设计原则、制备工艺、微观结构和力学性能进行了介绍,分析了现阶段轻质高熵合金研究的不足之处并对轻质高熵合金未来在生产生活中的应用进行了展望。
基金supported by the National High Technology Research and Development Program of China (863 Program) (Grant No.2009AA03Z214)the National Science Fund of China for Distinguished Young Scholars (Grant No. 50825103)+2 种基金the National Natural Science Foundation of China (Grant No. 51001112)the "Hundred of Talents Program" (Grant No. KGCX-2-YW-803) by Chinese Academy of Sciencesthe Fundamental Research Funds for the Central Universities (Grant No. 2010B15414)
文摘In this study, the soft magnetic properties and crystallization behavior of Fes3B10C6-xSixCul （x=0-4） nanocrystalline alloys prepared by annealing the melt-spun amorphous ribbons have been investigated. It is found that in the Fe83B10C6-xSixCU1 alloy system, the coercivity （Hc） decreases slightly with increasing Si addition and exhibits a minimum value with composition of x = 2, while the effective permeability （Ue） shows an opposite variation trend. The saturation magnetic flux density （Bs） shows a slightly decreasing trend owing to the decreasing volume fraction of nanocrystalline phase. The Fe83B10CaSi2Cu1 nanocrystalline alloy exhibits excellent soft magnetic properties with a high Bs of 1.78 T, high ue of 13 600 and low Hc of 4 A/m.
基金National Natural Science Foundation of China (51878246, 51979099)Natural Science Foundation of Jiangsu Province of China (BK20191303)Fundamental Research Funds for the Central Universities of Hohai University (B200202122&2019B768814)。
基金supported by the National Natural Science Foundation of China (Grant No. 51141002)the Fundamental Research Funds for the Central Universities (B1020270)Natural Science Foundation of Jiangsu Province of China (Grant No. BK2010521)
文摘In this paper,an InGaN metal-insulator-semiconductor(MIS) photodetector with an ultra-thin Al2O3 insulation layer deposited by atomic layer deposition(ALD) was studied.A high photoelectric responsivity of 0.25 A/W and a spectral responsivity rejection ratio of about three orders of magnitude at 1 V reverse bias were achieved for this MIS photodetector.The dominant carrier transport mechanism in the InGaN MIS photodetectors is submitted to the space charge limited current(SCLC) mechanism at high field and exhibits an Ohmic-like conduction at low electric field.The results indicate that the ultra-thin Al2O3 film deposited by the ALD technique can act as an excellent insulation dielectric for the InGaN photodetectors.
