Synthesis of Fe-Al-Ti Based Intermetallics with the Use of Laser Engineered Net Shaping (LENS)
The Laser Engineered Net Shaping (LENS) technique was combined with direct synthesis to fabricate L21-ordered Fe-Al-Ti based intermetallic alloys. It was found that ternary Fe-Al-Ti alloys can be synthesized using the LENS technique from a feedstock composed of a pre-alloyed Fe-Al powder and elemental Ti powder. The obtained average compositions of the ternary alloys after the laser deposition and subsequent annealing were quite close to the nominal compositions, but the distributions of the elements in the annealed samples recorded over a large area were inhomogeneous. No traces of pure Ti were observed in the deposited alloys. Macroscopic cracking and porosity were observed in all investigated alloys. The amount of porosity in the samples was less than 1.2 vol. %. It seems that the porosity originates from the porous pre-alloyed Fe-Al powders. Single-phase (L21), two-phase (L21-C14) and multiphase (L21-A2-C14) Fe-Al-Ti intermetallic alloys were obtained from the direct laser synthesis and annealing process. The most prominent feature of the ternary Fe-Al-Ti intermetallics synthesized by the LENS method is their fine-grained structure. The grain size is in the range of 3–5 μm, indicating grain refinement effect through the highly rapid cooling of the LENS process. The Fe-Al-Ti alloys synthesized by LENS and annealed at 1000 °C in the single-phase B2 region were prone to an essential grain growth. In contrast, the alloys annealed at 1000 °C in the two-phase L21-C14 region exhibited almost constant grain size values after the high-temperature annealing.
The Effect of the Traverse Feed Rate on the Microstructure and Mechanical Properties of Laser Deposited Fe3Al (Zr,B) Intermetallic Alloy
The results of the fabrication of components made with Fe-30%Al-0.35%Zr-0.1%B alloy powder using the Laser Engineered Net Shaping (LENSTM) system operated at different traverse feed rates are described in this paper. The temperature of the molten metal pool was recorded during this process. Depending on the assumed feed rate, the formation of Zr–based precipitates with various morphologies and distributions was observed in the structure of the investigated material. It was found that as the traverse speed increased, spheroidization, refinement, and a more homogeneous distribution of these precipitates occurred.
Beyond zero tolerance : discrimination in military culture
Chapter 1 Introduction: Rethinking Military Culture Part 2 Constructing Military Culture Chapter 3 Discrimination and Military Cohesion: An Organizational Perspective Chapter 4 Military Folk Culture Chapter 5 Dressed to Kill? The Paradox of Women in Military Uniforms Chapter 6 A Tangled Webb the Navy Can't Afford Chapter 7 Women at the U.S. Army War College Part 8 The Military, Society, and Policy Chapter 9 Reflections of Society: The Intersection of Race and Gender in the U.S. Army in World War II Chapter 10 Intersectionality: A Necessary Consideration for Women of Color in the Military? Chapter 11 In War and Peace: Incidence and Implications of Rape by Military Personnel Chapter 12 Persistence of Sexual Harassment: The Impact of Military Culture on Policy Implementation Chapter 13 A Culture of Silence: Consequences of Don't Ask, Don't Tell, Don't Pursue Chapter 14 Gender and Sexual Orientation Diversity in Modern Military Forces: Cross-National Patterns Chapter 15 Military Culture and Military Families