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A User’s Guide

Surface modification of titanium and titanium alloys: Technologies, developments, and future interests

Introduction Electron beam welding is a fusion welding process and can be used for welding a wide variety of metals, such as stainless steel, Inconel, copper and other variations of their grades. The metal thicknesses range from foils to thick metals sheets. In addition, two different metals or alloys can be welded together. E-beam welding has a vast variety of applications such as; electronics and packaging, automotive and aircraft industry, and in medical technology. In particular, down-hole tools for the oil and gas industry can be processed.

Electron Beam Welding

The poor impact toughness and flame retardant performance have greatly restricted the engineering application of epoxy thermoset. To obtain the high-performance epoxy composites, the renewable vanillin-based flame retardant toughening agent (PVSi) was synthesized and incorporated into epoxy. The use of PVSi macromolecules can significantly enhance the impact toughness of epoxy. With 5 wt% of PVSi, the impact strength of the epoxy was maximally raised by 189.69%, from 12.42 kJ/m2 of the neat EP to 35.98 kJ/m2 of EP/PVSi5 composites. The toughening effect of PVSi macromolecules on epoxy was closely linked to its structural features, such as the flexible phenylsiloxane, active imine and polar phosphaphenanthrene groups. Simultaneously, the EP/PVSi5 composites reached up to the V-0 rating in vertical burning test (UL-94) and 29.5% in limiting oxygen index (LOI), with only 0.27 wt% ultra-low phosphorus loading. Additionally, the suppressed heat release, the evidently reduced toxic pyrolytic volatiles, and the promoted charring capability of EP/PVSi composites can be obtained, with phosphaphenanthrene, phenylsiloxane and diaminodiphenylsulfone groups in PVSi macromolecules jointly playing a role. These results indicated the improved fire safety of epoxy. Furthermore, the free radical scavenging effect of P· and PO·, the fuel dilution effect of nonflammable NH3 and SO2, the catalytic charring effect of the pyrophosphoric acid and metaphosphoric acid, the charring-stability effect of phenylsiloxane group and the suppression effect of high-quality carbon layers were analyzed and summarized. It was expected that PVSi would pave the way for the development of more highly efficient flame retardant toughening agents and high-performance epoxy thermoset.

Renewable vanillin-based flame retardant toughening agent with ultra-low phosphorus loading for the fabrication of high-performance epoxy thermoset

Titanium alloys have been used extensively in industry fields including aviation, aerospace and automobile due to their excellent comprehensive properties. Research and development of advanced plastic forming technology are of great importance to manufacturing titanium products of high performance and lightweight with low cost and short cycle. This paper analyzes the development tendencies of titanium alloy forming technology. Recent achievements in precision forming, microstructure control and multi-scale simulation of titanium alloys are reviewed. The forming techniques of large-sale integral complex components are presented.

Recent developments in plastic forming technology of titanium alloys

In this paper, some technological problems (e.g. low drawability, high susceptibility to galling, spring-back) occurring in the sheet-titanium forming process are discussed. A numerical simulation of the stamping process was carried out with the Adina System v.8.3 based on the finite element method. The effects of friction, the holding-down force and tool geometry on the course of the stamping process were analysed. The mechanical and technological material data needed for the calculations were determined experimentally. The friction coefficients for the frictional pair: ”titanium – tool steel” for different lubricants and antiadhesive layers determined in the “strip drawing” test were found. The role played by lubrication and antiadhesive layers in preventing titanium “build-ups” on the tools is presented. The calculated results were then confirmed experimentally.

Stamping of Titanium Sheets

Forming of the titanium elements by bending

Titanium is most likely to play more important role in future civil applications. Its excellent properties such as: low density, high mechanical strength and good corrosion resistance give it some advantages and open the way for new applications both in modern technology and civil engineering. In many ways (e.g. specific strength, corrosion resistance) titanium, especially its alloys outstrip typical structural materials such as steel and aluminium alloys. The article discusses properties of titanium and its alloys, which are especially important in civil engineering applications due to their properties: low density, resistance to sea water and salty atmospheres of seashores, low coefficient of thermal expansion and excellent aesthetic qualities. Although the use of titanium in civil application is still limited it is expected that a demand for titanium building materials will steadily grow in the future. The characteristic titanium applications in the worldwide civil engineering are presented. It is highlighted that despite high cost of titanium relative to other materials, over a long span of 20 or more years titanium tends to be cheaper in terms of life-cycle costs. Furthermore, the article investigates the difficulties and opportunities associated with shaping titanium sheets. In the paper, some technological problems (e.g. low drawability, high susceptibility to galling and high spring-back) occurring in the sheet-titanium forming processes are discussed.

J. Adamus

Papers

Stamping of Titanium Sheets

Forming of the titanium elements by bending

Applications of Titanium Sheets in Modern Building Construction

EBW titanium sheets as material for drawn parts

Analysis of forming titanium welded blanks