Improvement of Room Temperature Ductility of Ti-40 50 at%Al Alloys through Microstructural Controll by Heat Treatment

改进%20of%20房间%20温度%20延展性%20of%20Ti-40%2050%20at%Al%20合金%20通过%20微观结构%20控制%20by%20加热%20处理

基本信息

批准号：
02452243
负责人：
KIKUCHI Makoto
金额：
$ 4.29万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

It has been commonly accepted that a microstructure consisting of gamma/ alpha_2/gamma lamellae improves the ductility of gamma titanium aluminides. In this program, we have established that there are two formation mechanisms of gamma/alpha_22/gamma lamellar microstructures, which we proposed to call as primary lamellar microstructure : P-LMS and discontinuously corsened lamellar microstructure : DC-LMS.1)Primary gamma/alpha_2/gamma lamellar microstructure : P-LMSFormation of the primary gamma/alpha_2/gamma lamellar microstructure was investigated using a Ti-40at%Al binary alloy. Upon quenching a disordered hcp alpha phase, stable at higher temperatures, to gamma+ alpha_2 two phase region, ordering from alpha to alpha_2 took place first, followed by precipitation of gamma plates on the basal plane of the alpha_2 matrix as a habit plane. Rapid lengthening of the gamma plates along the only one existing habit plane resulted in a seemingly perfect planar layer alignment of gamma and alpha_2 alternate lamellae. Variant distribution in the gamma plates was experimentally determined. Relative orientation relationships were discussed among independently grown gamma plates.2)Discontinuously corsened gamma/alpha_2/gamma lamellar microstructure : DC-LMS.Discontinuous coarsening(DC)of the P-LMS was studied in a temperature range between 1073 and 1473 K, using four Ti-Al binary alloys containing between 40 and 47 at%Al. DC started from the original alpha grain boundary. The migration rate of the advancing front of DC decreased with reaction time. The finer intelamellar spacing of P-LMS enhanced, while the larger volume fraction of alpha_2 phase beyond 50 pct in P-LMS inpeded, DC. DC divided a primary lamellar domain, whose size is the same as the original alpha grain size, into smaller colonies, within which not only the interlamellar spacing of the lamellae was larger, but also their alignment was less planar.

人们普遍认为，由γ/α_2/γ片层组成的微观结构提高了γ钛铝化物的延展性。在本项目中，我们确定了 gamma/alpha_22/gamma 层状微观结构的两种形成机制，我们建议将其称为初级层状微观结构：P-LMS 和不连续腐蚀层状微观结构：DC-LMS。1）初级伽马/ α_2/γ 层状微观结构：P-LMS 使用 P-LMS 研究初级 γ/α_2/γ 层状微观结构的形成Ti-40at%Al 二元合金。将在较高温度下稳定的无序 hcp α 相淬火至 gamma+ alpha_2 两相区时，首先发生从 α 到 alpha_2 的排序，然后在 alpha_2 基体的底面上沉淀出伽马板作为习惯平面。沿着唯一一个现有习惯平面的伽玛板的快速加长导致伽玛和α_2交替片层看似完美的平面层排列。伽玛板中的变体分布是通过实验确定的。讨论了独立生长的伽玛板之间的相对取向关系。2）不连续的伽玛/α_2/伽玛层状微观结构：DC-LMS。在1073和1473 K之间的温度范围内研究了P-LMS的不连续粗化（DC），使用四种含有 40 至 47 at% Al 的 Ti-Al 二元合金。 DC从原始的α晶界开始。 DC前进前沿的迁移速率随着反应时间的延长而降低。 P-LMS 的更细的片层间距增强，而 P-LMS 中 α_2 相的较大体积分数超过 50%，阻碍了 DC。 DC将大小与原始α晶粒尺寸相同的初级层状区域分成更小的集落，其中不仅片晶的层间距更大，而且它们的排列也不太平面。

项目成果

期刊论文数量（28）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Makoto KIKUCHI and Yoko YAMABE: "Mechnism of Formation of Primary gamma/alpha_2 Lamellar Microstructure in Titanium Aluminides" Proc. Jpn. Inst. Met. Symp. Intermetallic Compounds. 815-819 (1991)

Makoto KIKUCHI 和 Yoko YAMABE：“钛铝化物中初生 gamma/alpha_2 层状微观结构的形成机制”Proc。

DOI：
发表时间：
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影响因子：
0
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通讯作者：

Yoko YAMABE and Makoto KIKUCHI: "Evolution and Microstructure of gamma/alpha_2 Lamellar Microconstituent in Ti-Al Binary Alloys" Bulletin Jpn. Inst. Matals. 30[1]. 37-42 (1991)

Yoko YAMABE 和 Makoto KIKUCHI：“Ti-Al 二元合金中 gamma/alpha_2 层状微成分的演化和微观结构”，Bulletin Jpn。

DOI：
发表时间：
期刊：
影响因子：
0
作者：
通讯作者：

Yoko YAMABE and Makoto KIKUCHI: "Distribution of Variants in gamma Plates in Primary gamma/alpha_2 Lamellar Microstructure of a Ti-40at% Al Alloy" Mater. Sci. Eng.

洋子%20YAMABE%20和%20Makoto%20KIKUCHI:%20"分布%20of%20Variants%20in%20gamma%20Plates%20in%20Primary%20gamma/alpha_2%20Lamellar%20微观结构%20of%20a%20Ti-40at%%20Al%20Alloy"