首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 109 毫秒
1.
Hot workability of Ti-6%Al-4%V and two whisker discontinuously reinforced materials, Ti-6%Al-4%V/1.2%TiB and Ti-6%Al-4%V/8.9%TiB, have been investigated. Hot uniaxial compression tests were carried out using a computer controlled thermomechanical simulator Gleeble machine at temperatures in the range 850 °C to 950 °C and strain rates ranging from 1 to 50 s?1. The microstructures and the compression test results were compared among the three materials. The Ti-6%Al-4%V/8.9%TiB material presented extensive cracking after deformation. In contrast, the Ti-6%Al-4%V/1.2%TiB material showed an interesting compromise between flow stress and workability. The parameters of the Garofalo equation were calculated for the three materials revealing apparent activation energies that increased with increasing TiB content. The modelling is carried out by stability maps that gives the temperature at a given strain rate to obtain optimal workability and the stresses that has to bear the equipment. Taken 5 s?1 as a reference strain rate, the temperature required to obtain a quality product increased from about 1143 K (870 °C) for the Ti-6-4 alloy without TiB to 1228 K (955 °C) for the 1.2%TiB and to 1283 K (1010 °C) for the 8.9%TiB material. Therefore, the production of parts of the TiB composites should be conducted at a higher forming temperature to avoid the presence of cracks.  相似文献   

2.
Adiabatic shear banding is a phenomenon observed in machining titanium and some other metals and alloys as well. The shear localized chips are important in the chip disposal process, machined surface integrity and the automation of machining operations. It is therefore necessary to understand the mechanisms of metal cutting such as the formation of shear banding in the produced chips. In this paper, the behaviour of the chip formation is investigated using various metallurgical analysis techniques. It was found, in cutting Ti-6wt.%Al-4wt.%V titanium alloy, that some non-diffusional phase transformation took place in the shear localized chips. The process of chip formation with shear banding and the effects of cutting conditions on shear banding frequency were also studied. The results of these tests are presented in this paper.  相似文献   

3.
A.M. Irisarri  J.L. Barreda 《Vacuum》2009,84(3):393-399
The use of different procedures for electron beam welding of 17 mm thick Ti-6Al-4V plate and the difficulties found in this process are analysed. When this alloy was welded autogeneously the presence of significant amounts of α martensite was observed, recommending looking for another solution. In the early trials a V joint design was used but distortions and defects were detected in the welds when multi-pass procedures were considered. Consequently, for the remaining weldments K or I joint configurations were selected. Initially, Ti-6Al-4V wire was preferred in order to match mechanical properties with base material but no significant improvement was found leading to consideration of using a less alloyed filler metal. Different commercially pure titanium filler metals have been employed to optimise the performance of the fusion zone of electron beam weldments. In a second paper [1] the influence of the welding procedure on the mechanical properties of the various joints will be discussed.  相似文献   

4.
钛合金焊接凝固结晶控制的研究   总被引:2,自引:0,他引:2  
韩忠  赵晖  陈晓风 《材料导报》2000,14(4):10-12
由于焊缝金属中粗大的柱状β晶粒组织严重影响其力学性能及耐蚀性,钛合金焊接凝固结晶方面的研究工作一直颇受重视。综述了该方向有代表性的研究成果,并介绍了本人利用电子束扫描控制焊接凝固结晶取得的一些结果。  相似文献   

5.
The linear friction welding (LFW) of Ti-6Al-4V parts manufactured through electron beam melting (EBM) is investigated using different processing conditions of frequency (from 40 to 50 Hz) and pressure (from 55 to 75 MPa). The microstructure, hardness, and porosity of the different zones of the weld are analyzed in relation to the parent material. The experiments show that LFW is a viable technology for Ti-6Al-4V EBMed parts since it produces welds with hardness and microstructure comparable to those of the base material. Furthermore, the process is demonstrated to be quite robust in the range of specific power input going from ~0.7 to ~1.2 W/mm2. LFW of small EBMed parts to form larger components is of particular interest for the industrialization of titanium alloy aerospace components produced by means of additive manufacturing.  相似文献   

6.
简要概括了真空电子束焊接技术在不同材料连接方面的应用现状及研究发展动态,包括铝及其合金、钢铁材料、铜及铜合金、钛及钛合金、难熔金属钨/钽/铌/钼及其合金、金属间化合物及复合材料电子束焊接的发展现状。针对电子束焊接技术,简述了国内外学者已取得的部分研究成果,包括工艺试验、组织分析、数值模拟和力学性能等;分析了目前电子束焊接技术在材料连接方面还存在的问题,并展望了电子束焊接技术应向高温新型结构材料、异种材料、功能复合材料等方向发展,丰富了连接过程中的理论基础,揭示了工艺与组织及性能的对应关系,扩展了电子束焊接技术的应用领域。  相似文献   

7.
不锈钢和钛合金异种焊接在化工、航空和核工业等领域均有广泛的应用,但不锈钢和钛合金因理化性能的差异,焊接界面常形成大量脆性金属间化合物,无法得到优质的焊接结果。以扩散焊、激光焊和电子束焊为主总结了不同焊接方法的工艺参数和接头组织成分对不锈钢和钛合金焊接质量的影响,展望了不锈钢与钛合金异种金属焊接的发展趋势。  相似文献   

8.
船舶用钛合金焊接接头要求具有较好的抗冲击性能和抗疲劳性能,针对较大壁厚结构件,一般的焊接技术效率低且焊接质量较难保证,真空电子束焊接技术在这方面具有优势。本文综述了钛合金电子束焊接的特点,对其在船舶应用的前景,尤其是在大厚板焊接、冲击性能和疲劳性能等方面的优异表现进行了介绍,船舶用钛合金厚板焊接的长服役寿命可靠性是采用电子束焊接结构制造的根本目的。  相似文献   

9.
The influence of various filler metals on the mechanical properties of 17 mm thick Ti-6Al-4V electron beam welded joints has been analysed. Autogeneous welded joints exhibit higher toughness when compared to the parent plate but this improvement was less marked than that observed in plasma arc welded joints. To achieve better toughness, without suffering unacceptable losses of strength, different morphologies of commercially pure titanium filler metals have been employed. Using 0.50 mm thick sheet as filler metal leaded to maximum toughness but as counterpart a significant decrease in strength was observed. To obtain high toughness while maintaining a high strength level 0.25 mm sheet and 1 mm diameter filler metals are recommended. Fractographic examination of the failed specimens helped to explain the fracture behaviour of the different welded joints.  相似文献   

10.
综述了大厚度钛合金电子束焊接技术的研究进展,主要介绍了电子束深熔焊的原理特点,接头成形及缺陷控制、组织性能和残余应力分布等方面国内外的研究情况,明确了大厚度钛合金电子束焊接技术研究尚需解决的突出问题并展望了未来研究的发展方向。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号