Papers by Keyword: Fracture Control

Abstract: In recent years, self-healing research has been actively carried out to increase the life and stability of concrete structures. A representative method of concrete self-healing is a method using a bacterial substrate and a capsule. Bacteria-based self-healing is greatly influenced by the external environment, and sleeping structures are more suitable for capsule-based methods. In this study, the mechanical properties of the bonding surface of the photocurable resin are used to grow cracks in the capsule so that the self-healing capsule pops out and the healing liquid inside the capsule can be diffused efficiently. We proceeded with research to form pathways. The study analyzed the concordance rate of the bonding surface of the capsule and the judging position, and analyzed the factors affecting the concordance rate. As a result, by adjusting the number of bonding surfaces and the degree of air bubble removal, the rate of coincidence between the bonding surfaces and the fracture position was increased from 15.48% to 63.18% by a factor of 4.08.

Abstract: Temper embrittlement and fracture control method based on both non-equilibrium grain-boundary segregation (NGS) theory and grain refinement technique are studied in this paper. Grain refinement technique by deformation induced phase transformation in low-alloy steels, 12Gr1MoV and 2.25Gr1MoNb, is investigated. A single-pass hot rolling process by using a Gleeble-1500 system is performed. Experimental results show that steel strength and toughness may be controlled and improved by grain refinement, and that the grain sizes were affected by the deforming temperature, strain reduction, and strain rate. According to the NGS theory, a control method of brittle fracture along grain-boundary is proposed so that some catastrophically brittle fracture failure may be averted. Grain refinement may decrease both the concentration of phosphorus at grain boundaries and the critical time. With the grain refinement technique, the temper embrittlement of steel may be improved, and the critical time may be shortened. The cost of heat treatment for fracture control will therefore be reduced.

Abstract: In last two decades it has been extensively studied whether the grain boundary engineering can be effectively applied to controlling intergranular fracture and brittleness of different kinds of brittle materials. Grain boundary engineering has been well established. A new processing method based on magnetic field application has reached a new stage of grain boundary engineering.