TC11钛合金压气机盘闭模锻造过程中的缺陷预测

TC11钛合金压气机盘在实际生产中存在各种缺陷,降低了压气机盘的使用性能.将基于试验数据建立的TC11钛合金高温塑性变形时的延性损伤演化模型以及本构模型与有限元相结合,对某TC11钛合金压气机盘等温闭模锻造过程中的温度、等效应变和损伤变量的分布进行了数值分析,同时预测了塑性失稳区的位置.为优化其成形工艺提供了一种有效的方法.     

Hot deformation mechanism and microstructure evolution of TC 11 titanium alloy in β field

Hot deformation behaviors of TC11 alloy with β-annealed larnellar structure and forged equiaxed structure were investigated in the β field in the temperature range of 1 090-1 030 ℃ and strain rate of 0.001-0.1 s-1. By means of isothermal compression tests. Hot deformation characteristics and microstructure evolutions of the two starting structures were analyzed. And hot processing power dissipation efficiency maps were established. EBSD technique was used for testing grain boundary characteristic of deformation structures. The results indicate that hot deformation mechanism of TC11 alloy in β field is dynamic recovery accompanied by geometric dynamic recrystallization at large strains, or discontinuous dynamic reerystallization based on the starting structure states and deformation parameters. Accordingly, there are two different grain refining patterns. One is characteristic of new fine grains in the interior of elongated prior β grains that have serrated grain boundaries; and the other is that of new fine grains along elongated prior β grain boundaries.     

TC11钛合金高温变形本构关系研究

在Thermecmastor-Z型热加工模拟试验机上,对TC11钛合金在990℃～1080℃、0.001s-1～70s-1范围内进行了高温压缩实验。通过真应力-真应变曲线,分析了流动应力随变形热力参数的变化规律,并在Arrhenius方程的基础上考虑了真应变对流动应力的影响,构建出TC11钛合金的本构关系。误差分析表明,该本构方程有较好的精度,可适合于工程应用。     

Ti＋48Al＋B合金中硼化物的生长机理

研究了Ti-48Al (0.2～0.8)at%B合金中硼化物的生长机理。结果显示：合金中的硼化物均为C32结构的TiB2相;在加入0.2at%和0.5at%B的合金中只存在带状TiB2相;而加入0.8at%B的合金中除带状TiB2相外,还出现了少量六方形貌的块状TiB2相,块状硼化物是从液相中自由生长的初生TiB2相,其惯习面为（0001）基面和｛10∧-10｝柱面;而带状硼化物则是次生TiB2相,是通过L→β TiB2和L β→α TiB2反应与基体耦合生长的非规则共晶反应产物。两种形貌的TiB2颗粒均以台阶方式生长。     

钛合金高温形变强韧化机理

详细研究并讨论了钛合金高温形变强韧化机理。结果表明,三态组织中少量等轴α相与基体β相没有固定的位向关系,位错容易找到可开动的滑移面,对变形起着协调作用,因而合金具有较高的塑性;大量网篮交织的条状α,不仅增加了相界面,提高了合金的强度与抗蠕变能力,而且不断改变裂纹扩展方向,导致裂纹路径曲线、分枝多,断裂韧性好。新的变形理论适用于α,近α,（α＋β）和近β型钛合金。     

从角到圆的蜕变——写在《材料工程》创刊55周年

一本名为《失落的一角遇见大圆满》图画书很有意思:失落的△形一角孤独地等着有人把它带走。为了引起注意,它打扮自己,试着变得醒目,终于有一天它遇到个可以带着它走的,可是,没有多久它们又分道扬镳了。直到它遇到〇形的大圆满,     

职业素质视角下高职院校学生"职业化"培训的实践与探索

为了切实提高高职院校学生的职业素质,满足企业尤其是电力企业对职业素质的要求,学院引入了旨在提高学生职业素质的"职业化"培训体系,即将"职业化"培训体系中的5S现场管理、定置管理、目视管理、看板管理和学习型团队建设全面融入到专业教学体系中,开设课内和课外的"职业化"课程,并将"职业化"理念渗透到各教学环节,从而实现培养高素质技能型人才的教育教学目标.     

Effect of size and distribution of titanium carbide on microstructure and mechanical properties of Ti-25V-15Cr-2Al-0.2C-0.2Si alloy

The effect of size and distribution of titanium carbide on the microstructure and mechanical properties of non-burning β titanium alloy Ti-25V-15Cr-2Al-0.2C-0. 2Si （mass fraction, %） was investigated. The microstructure of the heat-treated and exposed alloy was studied using optical microscopy（OM）, scanning electron microscopy （SEM） and transmission electron microscopy（TEM）. It is found that carbides with finer size and more uniform distribution can suppress the formation of α precipitates more effectively, and can especially decrease the amount of grain boundary α precipitates after long-term exposure at 540 ℃ （the expected application temperature）. Thus, significant improvement in thermal stability can be achieved by refining carbide particles in the matrix of the alloy.     

Heat treatment process for improving ductility of Ti-25V-15Cr-2Al-0.2C alloy

1　INTRODUCTIONBetatitaniumalloyshavebeenextensivelystud iedforabout 5 0 yearssinceTi 13V 11Cr 3Alalloywasfirstdevelopedin 195 2 [1] .Thesealloysareat tractiveintermsoftheirhighstrengthandexcellentcoldformability .However ,theapplicationofthesealloyswaslimitedinthepast ,possiblyduetotheirhigherpricesandprocessingdifficulties .Intheearly1990s,anew βtitaniumalloy ,calledalloyC (Ti 35V 15Cr) ,wasdevelopedintheUSA ,whichsuc cessfullycombines goodmechanical propertiesandburningresistance[…     

高温钛合金制造技术研究进展

高温钛合金制造技术已成为先进航空发动机技术的核心与关键,近年来受到高度重视。在简要回顾新型高温钛合金、阻燃钛合金和Ti-Al系金属间化合物合金发展的基础上,从大规格铸锭熔炼、挤压开坯、整体叶盘模锻、环件轧制及零件机加工等方面介绍这些高温钛合金制造技术研究所取得的重要进展。最后,提出我国高温钛合金应用研究中需要重点关注的问题以及进一步发展的建议。