William E. Frazier

Metal Additive Manufacturing: A Review

This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.

The Effect of Thermal Exposure on the Mechanical Properties of 2099-T6 Die Forgings, 2099-T83 Extrusions, 7075-T7651 Plate, 7085-T7452 Die Forgings, 7085-T7651 Plate, and 2397-T87 Plate Aluminum Alloys

Aluminum alloys 2099-T6 die forgings, 2099-T83 extrusions, 7075-T7651 plate, 7085-T7452 die forgings, 7085-T7651 plate, and 2397-T87 plate were thermally exposed at temperatures of 180 °C (350 °F), 230 °C (450 °F), and 290 °C (550 °F) for 0.1, 0.5, 2, 10, 100, and 1000 h. The purpose of this study was to determine the effect of thermal exposure on the mechanical properties and electrical conductivity of these alloys. The data shows that higher temperatures and longer exposure times generally resulted in decreased strength and hardness and increased percent elongation and electrical conductivity.

Advanced lightweight alloys for aerospace applications

The design requirements of the next generation of advanced aerospace vehicles and propulsion systems necessitate the development of structural materials with properties vastly superior to those which are currently achievable. Recognizing that each class of materials possesses its own unique set of advantages and disadvantages, the designers of tomorrow’s aircraft must choose wisely from the plethora of available alloys.

The melt spinning of gamma titanium aluminides

Rapid solidification shows great promise for the production of gamma titanium aluminides, and one of the most interesting rapid solidification techniques is melt spinning. In this work, melt-spun Ti-5SAl and Ti-48Al-2Cr-2Ta (atomic percent) were produced; the resulting alloys had uniform microstructure and composition. In addition, the investigation showed the utility of a model developed to describe heat transfer and fluid flow in melt spinning.

The qualification of metallic materials

The materials engineer, who is responsible for the selection, qualification, and certification of materials technologies, plays a crucial role in assuring the safety and structural integrity of product designs. The methodology used to certify materials technologies must be thoughtful and robust to account for all factors that may affect a material’s suitability. The materials engineer must also execute the implementation plan in a disciplined manner. Two papers are presented on the topic of materials selection and qualification. The first details the process by which the U.S. Navy qualifies metallic materials and metallic airframe structures. The navy’s unique operational requirements and environment provide the drivers for the certification process. As indicated, a close interaction between the engineering disciplines for structures and mateThe Qualification of Metallic Materials