Location: Woolsey Hall, Room 110A (Auditorium #1)

The National Institute of Aviation Research (NIAR) and the College of Engineering are hosting a seminar entitled, "Hidden Science in Engineering Materials." The seminar will feature the below talks and speakers at 3 p.m. on Thursday, April 24. 

General event description:
The Sun shines, planets move, and plants grow. These natural phenomena are better understood after the scientific discoveries of nuclear fusion, Newton mechanics, and Calvin cycle. How about human-invented applied materials? Progress in the recently advanced nanotechnology tends to have science leading material synthesis. In contrast, however, most standard engineering materials for large-scale applications are developed empirically, then modified and improved with experience through usage data. They serve well their designated purposes. But, if possible, shouldn’t we try to bring in some scientific insights, which may be beneficial to further material development or evaluation?

1. "What does low-temperature calorimetry tell us about high-strength Al-Li, Ti-(V, Mo)-Al, and magnetic element-containing materials?" by James C. Ho
   Talk description: Technical approaches toward alloy development and evaluation are mostly empirical. This is deemed justified, considering the complex metallurgical mechanisms involved. But, if possible, shouldn’t we try to bring in some scientific insights? This talk represents one example, which is based on the physics concept of free electrons. These delocalized valence electrons move throughout the lattice, creating an attractive electrostatic force with the positively charged ions. The non-directional cohesion yields the strength and ductility of metallic systems. Of particular interest here is the dilute alloying effect in high-strength Al-Li and Ti-(V, Mo)-Al, apart from the obvious advantage of lower densities. Data analysis of their electronic specific heat, obtained calorimetrically at cryogenic temperatures of a few degrees Kelvin to minimize lattice vibrations, indicates electron localization presumably between host and alloying elements. The randomly distributed directional bond-like arrangements could be responsible for enhancing strength but reducing ductility as observed. Meanwhile, low-temperature calorimetry also reveals magnetic clusters formation in magnetic element-containing tungsten-2, nickel-based superalloy, and polycrystalline Ni₃Al, but not in single-crystal Ni₃Al. Such magnetically-induced submicroscopic inhomogeneities could in turn affect crack growth and fatigue behaviors.
2. "Failure Mechanism of Fiber Reinforced Composites for Aviation" by Ramazan Asmatulu
   Talk description: The thermal oxidative stability of aerospace grade fire retardant fiber composites is a critical factor determining their performance and durability in high-temperature and oxidative environments. These composites, commonly used in aircraft and spacecraft applications, are subjected to extreme conditions during operation, necessitating a thorough understanding of their thermal and oxidative degradation mechanisms. In this study, thermal oxidative stability of carbon and glass fiber-reinforced polymer composites was investigated by employing a combination of experimental techniques, including thermogravimetric analysis, dynamic mechanical analysis, and isothermal aging in an air-circulating oven. The aged sample was removed at regular intervals (100h, 250h, 500h, 750h, and 1000h) and weight loss was recorded until the completion of 1000 hours. Short beam shear (SBS) tests were conducted on the composite samples to examine the impact of thermal aging on the mechanical properties of the materials under simulated operational conditions. The test results demonstrated good thermal stability for both composite materials, evidenced by a glass transition temperature and a weight loss of less than 0.3%. Also, about 10% and 7% drop in interlaminar shear strength was observed in carbon and glass fiber composites, respectively. The outcomes of this research have significant implications for the design, manufacturing, and optimization of aerospace grade fire retardant fiber composites, ultimately contributing to improved safety, reliability, and performance in demanding aerospace applications.
3. "Qualification of Additively Manufactured Metals” by Rachael Andrulonis
   Talk description: Additive manufacturing (AM), also known as 3-D printing, is the process of joining materials to make parts from 3D model data usually layer upon layer, as opposed to subtractive manufacturing and formative manufacturing methodologies. AM can be used in various applications and offers significant design flexibility. However, the aviation industry has not been able to fully embrace the promise of additive due to a number of factors, including the ability to reliably and repeatedly print AM parts. A common understanding of a practical qualification framework and a robust set of qualified materials and processes are needed to advance AM. Qualified materials and processes require the creation of a material allowable dataset collating substantial time and financial investments including manufacturing, testing, and analysis of hundreds of test coupons.   During this presentation, an overview of the methods to qualify metallic AM materials and parts safely for aviation applications will be presented along with current activities at 暗网禁区破解版 to advance the insertion of these materials throughout the aerospace industry.