Several 35CrMo4 and 38MnV7 steels with different additions of Ti and V were manufactured by electroslag remelting. The influence of the alloying and microalloying elements on phase transformation at different cooling ...Several 35CrMo4 and 38MnV7 steels with different additions of Ti and V were manufactured by electroslag remelting. The influence of the alloying and microalloying elements on phase transformation at different cooling rates was studied and the continuous cooling transformation diagrams were plotted. In order to optimize the heat treatment and improve the mechanical properties, the range of cooling rates leading to a fully bainitic microstructure （without ferrite, pearlite and especially without martensite） was determined. Bainite and martensite transformation start temperatures （Bs, Ms） were also established and compared with the values predicted by empirical equations. The important role of precipitates （especially V carbonitride particles） on final microstructure and mechanical properties was assessed.展开更多
La-Y-Ni alloys exhibit high discharge capacity due to the formation of AB_(3-3.8)-type(A=La,Y;B=Ni)intermetallic compounds.However,the stable composition and temperature range for this type of phase are rarely reporte...La-Y-Ni alloys exhibit high discharge capacity due to the formation of AB_(3-3.8)-type(A=La,Y;B=Ni)intermetallic compounds.However,the stable composition and temperature range for this type of phase are rarely reported,which restrains the development of La-Y-Ni hydrogen storage alloys with stable structure and high capacity.This paper focuses on the phase equilibria of the La-Y-Ni ternary system in Ni-rich corner.The phase constitution,microstructure,and equilibrated composition were experimentally determined at 1273 and 1148 K using X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy-dispersive spectroscopy(EDS).The solubilities of La and Y in the binary compounds were measured.Two ternary compounds,3R-LaY_(2)Ni_(9)with the structure of PuNi3 type and La_(0.5)Y_(0.5)Ni_(5)with the structure of CaCu5 type,existed at both temperatures.Based on the experimental data,the thermodynamic description of LaY-Ni system was assessed by Calculation of Phase Diagram method.The calculated isothermal sections agree with the experimental data.The thermodynamic database is helpful for the design of La-Y-Ni hydrogen storage alloys.展开更多
The continuous cooling transformation (CCT) diagrams of 86CrMoV7 steel samples including hot deformed and not hot deformed were constructed by dilatometry, metallography and transmission electron microscopy (TEM). The...The continuous cooling transformation (CCT) diagrams of 86CrMoV7 steel samples including hot deformed and not hot deformed were constructed by dilatometry, metallography and transmission electron microscopy (TEM). The results showed that hot deformation accelerated pearlite transformation and fine pearlite microstructure. Moreover, the undissolved carbides became the nucleating sites of pearlite, accelerated pearlite formation and fine pearlite if the steel had been deformed at high temperature. In contrast, undissolved carbides did not make any influence on pearlite transformation if the steel had not been deformed at high temperature.展开更多
面向海洋、航空、核能等重大工程中涂层的表面损伤与防护研究,精确的相图与相变信息是高效研发高性能可靠涂层材料的关键。但是,涂层制备一般是非平衡的成相过程,涂层在苛刻环境中服役处于动态相变过程,因此,基于热力学平衡的传统相图计...面向海洋、航空、核能等重大工程中涂层的表面损伤与防护研究,精确的相图与相变信息是高效研发高性能可靠涂层材料的关键。但是,涂层制备一般是非平衡的成相过程,涂层在苛刻环境中服役处于动态相变过程,因此,基于热力学平衡的传统相图计算CALPHAD(CALculation of PHAse Diagrams)方法不再适用于涂层材料设计。概述了涂层相图、相变研究及其应用于涂层材料设计的研究进展,重点评述了耦合CALPHAD、第一性原理计算和高通量实验方法的关键作用;从材料制备、动态服役和数据库指导材料开发3个方面出发,以典型的纯元素、二元、三元和多元材料体系为实例,介绍了亚稳相图模型、相变模拟与相图数据库在涂层材料研发中的应用;最后,提出了苛刻环境服役涂层相图、相变与材料设计目前面临的问题和挑战。展开更多
基金the financial support of Spanish Ministry of Economy and Competitiveness through the project ref.MAT2011-29039-C02-02
文摘Several 35CrMo4 and 38MnV7 steels with different additions of Ti and V were manufactured by electroslag remelting. The influence of the alloying and microalloying elements on phase transformation at different cooling rates was studied and the continuous cooling transformation diagrams were plotted. In order to optimize the heat treatment and improve the mechanical properties, the range of cooling rates leading to a fully bainitic microstructure （without ferrite, pearlite and especially without martensite） was determined. Bainite and martensite transformation start temperatures （Bs, Ms） were also established and compared with the values predicted by empirical equations. The important role of precipitates （especially V carbonitride particles） on final microstructure and mechanical properties was assessed.
基金financially supported by the National Key R&D Program of China(No.2021YFB3502200)National Natural Science Foundation of China(No.51734002)+1 种基金Science and Technology Committee of Shanghai(Nos.19010500400 and 19DZ2252900)Shanghai Rising-Star Program(No.21QA1403200)。
文摘La-Y-Ni alloys exhibit high discharge capacity due to the formation of AB_(3-3.8)-type(A=La,Y;B=Ni)intermetallic compounds.However,the stable composition and temperature range for this type of phase are rarely reported,which restrains the development of La-Y-Ni hydrogen storage alloys with stable structure and high capacity.This paper focuses on the phase equilibria of the La-Y-Ni ternary system in Ni-rich corner.The phase constitution,microstructure,and equilibrated composition were experimentally determined at 1273 and 1148 K using X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy-dispersive spectroscopy(EDS).The solubilities of La and Y in the binary compounds were measured.Two ternary compounds,3R-LaY_(2)Ni_(9)with the structure of PuNi3 type and La_(0.5)Y_(0.5)Ni_(5)with the structure of CaCu5 type,existed at both temperatures.Based on the experimental data,the thermodynamic description of LaY-Ni system was assessed by Calculation of Phase Diagram method.The calculated isothermal sections agree with the experimental data.The thermodynamic database is helpful for the design of La-Y-Ni hydrogen storage alloys.
文摘The continuous cooling transformation (CCT) diagrams of 86CrMoV7 steel samples including hot deformed and not hot deformed were constructed by dilatometry, metallography and transmission electron microscopy (TEM). The results showed that hot deformation accelerated pearlite transformation and fine pearlite microstructure. Moreover, the undissolved carbides became the nucleating sites of pearlite, accelerated pearlite formation and fine pearlite if the steel had been deformed at high temperature. In contrast, undissolved carbides did not make any influence on pearlite transformation if the steel had not been deformed at high temperature.
文摘面向海洋、航空、核能等重大工程中涂层的表面损伤与防护研究,精确的相图与相变信息是高效研发高性能可靠涂层材料的关键。但是,涂层制备一般是非平衡的成相过程,涂层在苛刻环境中服役处于动态相变过程,因此,基于热力学平衡的传统相图计算CALPHAD(CALculation of PHAse Diagrams)方法不再适用于涂层材料设计。概述了涂层相图、相变研究及其应用于涂层材料设计的研究进展,重点评述了耦合CALPHAD、第一性原理计算和高通量实验方法的关键作用;从材料制备、动态服役和数据库指导材料开发3个方面出发,以典型的纯元素、二元、三元和多元材料体系为实例,介绍了亚稳相图模型、相变模拟与相图数据库在涂层材料研发中的应用;最后,提出了苛刻环境服役涂层相图、相变与材料设计目前面临的问题和挑战。
