Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-19 Cooperative journals: 《金属学报》
Abstract： High strength micro-alloyed steel has been widely used in automobile and machines because of the remarkable high strength and forming property which are attributed to nano-precipitates and refinement of the organization. Since the nano-precipitates are mostly nucleated between austenite/ferrite transition and ferrite can significantly advance strength, it is important to investigate precipitate behavior in coiling process. Nanoindentation technology provides a chance to study the special influence of nano-precipitates on the micro-properties of ferrite. The effect of cooling rate during continuous cooling process and coiling process on microstructural evolution and micro-hardness of Nb-Ti micro-alloyed steel were studied by using the thermal mechanical simulator, micro-hardness instrument, TEM and nanoindentation instrument. The precipitate behaviors of (Nb,Ti)C in coiling process and its effect on nano-hardnesss of ferrite were discussed. Experiments results indicated that the increase of cooling rate in continuous cooling process and coiling process could promote the microstructure transition from ferrite and pearlite to bainite. The micro-hardness of the tested steel increased with the increase of cooling rate in continuous cooling process, and decreased with the cooling rate in coiling process because of the large number of the dispersive nano-precipitate in ferrite which could improve the strength of matrix. The smaller cooling rate could promote volume fraction of (Nb, Ti)C particles in ferrite because there was enough time for the nucleation and growth of (Nb, Ti)C precipitates. When the cooling rate in coiling process was 0.1 ℃/s, precipitates were dispersive in ferrite matrix with a diameter of less than 10 nm. The nanohardness and Young's modulus of ferrite were 4.13 and 249.3 GPa for Nb-Ti micro-alloyed steel, 2.64 and 237.4 GPa for C-Si-Mn steel. The contribution of nano-precipitates to nanohardness of ferrite reached 1.49 GPa.
Subjects: Information Science and Systems Science >> Other Disciplines of Information Science and Systems Science submitted time 2022-03-09
Abstract： 目的 论述建构信息系统动力学的必要性和基础，介绍其基本结构和应用前景。 方法 根据信息模型、性质和度量的数学基础理论以及信息系统的框架结构，建立信息系统的度量功效和动力构型，运用实例说明信息系统动力学的应用成前景。 结果 证明了信息模型、性质和度量定义符合一系列经典信息科技原理，基于信息系统的十一种度量功效和八种典型动力构型，构成了具有普遍意义的信息系统动力学基础理论体系。 局限 相关理论方法需要在其它行业领域复杂信息系统体系中得到应用验证。 结论 基于客观信息论的信息系统动力学能够支持复杂信息系统体系的分析和评价。
Peer Review Status:
Awaiting Review
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