The Effects of Carbon Content on the Formation of Ti2CS and the Fracture Toughness of Ultra-High Strength Steels

碳含量对超高强钢Ti2CS形成及断裂韧性的影响

• 批准号: 9712620
• 负责人: Warren Garrison
• 金额: $ 31.54万
• 依托单位: Carnegie-Mellon University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-12-01 至 2001-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9712620&HistoricalAwards=false
• 关键词: Effects; Carbon; Content; Formation; Ti2CS

9712620 Garrison The objective of this research is to investigate the effects of carbon content on sulfide formation and void nucleation resistance in titanium-modified steels. It is hypothesized that increasing the carbon content of titanium-modified steels causes the precipitate particles of the Ti2CS sulfide to be formed at higher temperatures, thereby producing larger sulfide sizes. Since the void nucleation resistance of Ti2CS particles is expected to decrease with increasing particle size, tying up sulfur as Ti2CS should be less effective in improving fracture toughness as the carbon content increases. If it is confirmed that increasing the carbon content increases the sulfide size and diminishes the void nucleation resistance in the titanium-modified steels, then methods will be explored to: (1) refine the sulfide size when the sulfur is gettered as Ti2CS, or (2) create new methods of gettering the sulfur into void nucleation resistant particles that remain effective at higher carbon levels. One approach that will be considered is to dissolve the sulfides and later reprecipitate them at lower temperatures in the austenite. If the sulfide size is refined by this approach and the reprecipitated sulfides are Ti2CS, then the toughness of higher carbon steels which contain reprecipitated sulfides will be investigated as well as the void nucleation resistance behavior of these finer reprecipitated sulfides. Gettering sulfur as Nb2CS rather than as Ti2CS will also be considered. Recent results suggest that this is feasible and that such particles are resistant to void nucleation. %% This research explores microstructural factors that influence the fracture behavior of structural steels. It has potential impact on the design of fracture-resistant metal alloys that could be employed in structures with improved lifetimes and safety. ***

小行星9712620 本研究的目的是研究碳含量对钛变质钢中硫化物形成和抗空洞形核性的影响。 据推测，增加钛改性钢的碳含量会导致在更高的温度下形成Ti2 CS硫化物的沉淀颗粒，从而产生更大的硫化物尺寸。 由于预期Ti2CS颗粒的空隙成核阻力随着颗粒尺寸的增加而降低，因此随着碳含量的增加，将硫束缚为Ti2CS在改善断裂韧性方面应该不太有效。 如果证实增加碳含量增加硫化物尺寸并减小钛改性钢中的空隙成核阻力，则将探索方法以：（1）当硫作为Ti2CS吸杂时细化硫化物尺寸，或（2）创造将硫吸杂到在较高碳水平下保持有效的空隙成核阻力颗粒中的新方法。 将考虑的一种方法是溶解硫化物，然后在奥氏体中在较低温度下使它们再沉淀。 如果硫化物尺寸通过这种方法细化并且再沉淀的硫化物是Ti2CS，则将研究含有再沉淀硫化物的高碳钢的韧性以及这些更细的再沉淀硫化物的空隙成核阻力行为。 还将考虑将硫作为Nb2CS而不是Ti2CS吸除。 最近的研究结果表明，这是可行的，这种颗粒是抵抗空隙成核。 本研究探讨了影响结构钢断裂行为的微观结构因素。 它对耐腐蚀金属合金的设计具有潜在的影响，这些合金可用于具有更长寿命和更高安全性的结构中。 ***