Statistically Guided Development of Laser-Assisted Cold Spray for Microstructural Control of Ti-6Al-4V
- PDF / 5,737,755 Bytes
- 13 Pages / 593.972 x 792 pts Page_size
- 87 Downloads / 133 Views
INTRODUCTION
TITANIUM is well known for its biomedical and chemical applications, but perhaps most notable is its prevalence in the aerospace industry. Titanium alloys will contribute up to 15 pct by weight in aircraft such as the Boeing 787 with global demand for these and similar aircraft valued at $4.4 trillion over the next 20 years.[1,2] With titanium use in these aircraft estimated to increase during that time period, commercial aerospace alone represents a significant market for the titanium industry with industries such as biomedical and defense aerospace furthering the demand for titanium as a material of choice.[1] Properties like high strength-to-weight ratio, high operating temperatures, corrosion resistance, and fatigue resistance are all driving factors for these industries to use titanium as an engineering material.[3] One of the problems facing titanium as the material for even more applications is its expense not only to extract, but also to manufacture into commercial components. The average buy-to-fly ratio for titanium is 8 to 1, meaning that for every ton of titanium used on an airplane, 8 tons will be purchased.[4] These high scrap rates have pushed many in the industry to investigate additive or near-net shape manufacturing techniques
AARON M. BIRT, RICHARD D. SISSON, Jr., and DIRAN APELIAN are with the Metal Processing Institute, Worcester Polytechnic Institute, 100 Institute Rd., Washburn Shops Office 315, Worcester, MA 01609. Contact e-mails: [email protected], birt. [email protected] VICTOR K. CHAMPAGNE, Jr. is with the U.S. Army Research Laboratory, Rodman Building, Aberdeen Proving Ground, Adelphi, MD. Manuscript submitted August 24, 2016. METALLURGICAL AND MATERIALS TRANSACTIONS A
such as electron beam additive manufacturing, selective laser sintering, laser engineered net shaping, and electron beam melting as possible replacement processes.[5–9] Most of these processes, while different in practice, are relatively similar in the basic concept; the temperature of a feedstock is raised to at or near melting conditions and very thin 2D layers are stacked to form three-dimensional objects. Another field of near-net shape manufacturing that has emerged in the past 10-15 years utilizes kinetic energy to deposit materials in the solid state. Such techniques include kinetic metallization, cold gas dynamic spray, supersonic spray, cold spray, and even warm gas dynamic spray.[10–14] The advantages of depositing materials in the solid state include lower oxidation, extreme working of the material, deposition of reactive materials, and high compressive residual stresses.[10,12,15,16] In general, these processes use a carrier gas, helium or nitrogen, at elevated temperatures and pressures to accelerate feedstock powder through a converging–diverging nozzle to high velocities commonly exceeding supersonic speeds. Several studies have been produced regarding the properties of cold-sprayed commercially pure (CP) titanium and have shown promise. Results for cold spray and laser-assisted cold spray (LACS) of CP
Data Loading...
