Preparation of 5N grade tantalum by electron beam melting

The texture and the bulk stored energy along the thickness direction were extremely inhomogeneous in the clock-rolled tantalum sheets with 70% reduction. Therefore, the effects of different annealing temperatures on the microstructure and texture distribution of tantalum plates through the thickness were investigated by X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). The results showed that the occurrence of strong {111} recrystallization texture in the center layer can be attributed to the subgrains nucleation mechanism when annealed at the low temperature. Many subgrains with {111} orientation appeared in the center layer, due to its high stored energy and preferential nucleation sites of the {111} deformed matrix, and rapidly grew into the effective nucleus, resulting in the large {111} grain size and strong {111} texture after complete recrystallization. Contrarily, at the high temperature, high-angle grain boundaries had sufficient driving force to generate migration, due to the lack of recovery, and the growth time of recrystallized nucleus was much shorter, contributing to relatively uniform recrystallization microstructure and texture distribution along the thickness.

Section: Introductionmentioning

confidence: 99%

The Effect of Different Annealing Temperatures on Recrystallization Microstructure and Texture of Clock-Rolled Tantalum Plates with Strong Texture Gradient

Zhu

Liu

Yang

et al. 2019

“…Furthermore, the electron beam can be controlled accurately in order to acquire the ingots with an excellent surface quality and solidification structure [12,13]. Recently, this melting technology has been utilized to purify solar-grade silicon [14,15], as well as to refine refractory metals [16], superalloys [17,18], and titanium alloys [19,20].…”

Section: Introductionmentioning

confidence: 99%

Volatilization Behavior of β-Type Ti-Mo Alloy Manufactured by Electron Beam Melting

Yao

Min

Shi

et al. 2018

The effects of electron beam melting parameters on the volatilization behavior of elements and the microstructures of ingots were investigated on a β-type Ti-Mo binary alloy. The microstructures of the ingots consisted of large and columnar grains at their bottom and top sections, respectively, and they were similar at different melting powers, from 10.5 kW to 15.0 kW, and the melting time ranging from 10 min to 40 min, without apparent metallurgical defects. Mass losses of ingots exhibited an increasing tendency, with increases of both melting power and melting time. Combined with a theoretical calculation and X-ray fluorescence results, Ti was identified as the main volatilization element due to its much higher vapor pressure than that of the Mo element. The considerable compensation method of the volatile Ti element was established in terms of theoretical and experimental results, which could provide a guidance for fabricating composition-controllable Ti-Mo binary alloys via electron beam melting technology.

“…It assures a superior level of refining and a high level of flexibility of the e-beam heat source (high energy density). This technology is mainly used for melting and refining of refractory and reactive metals, such as tantalum [9,10], niobium [6,11], ruthenium [12], molybdenum [13], iridium [14], vanadium, titanium [7,[15][16][17], etc., and their alloys. This method plays an important role in the production of ultrapure sputtering target materials and electronic alloys [9,12], in metal regeneration from waste products [3,18], in the metallurgical-grade silicon purification for the photovoltaic industry [8,[19][20][21], etc.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Tantalum Recycling by Electron Beam Melting

Vutova

Vassileva

Koleva

et al. 2016

Abstract:Investigations are carried out and obtained experimental and theoretical data for tantalum scrap recycling by electron beam melting (EBM) is presented in this paper. Different thermal treatment process conditions are realized and results are discussed. A chemical analysis is performed and refining mechanisms for electron beam (EB) refining of Ta are discussed. For the performed experiments the best purification of Ta (99.96) is obtained at 21.6 kW beam power for a melting time of 3 min. A statistical approach is applied for estimation of the material losses and the liquid pool characteristics based on experimentally-obtained data. The aim is to improve the EBM and choosing optimal process conditions, depending on the concrete characteristic requirements. Model-based quality optimization of electron beam melting and refining (EBMR) processes of Ta is considered related to the optimization of the molten pool parameters, connected to the occurring refining processes, and to minimal material losses. Optimization of the process of EBM of Ta is based on overall criteria, giving compromised solutions, depending on the requirements concerning the quality of the performed products. The accumulated data, the obtained results, and the optimization statistical approach allow us to formulate requirements on the process parameters.