USC McNAIR Adds 2400°C Furnace for Aerospace Composite Scale-Up

University of South Carolina’s McNAIR Center for Aerospace Innovation and Research has added a new large ultra-high-temperature furnace system to its 42,000-sq. ft. advanced manufacturing center in Columbia, SC, contributing to the growing body of advanced aerospace materials processing infrastructure in the United States.

Manufactured by Materials Research Furnaces of Allenstown, NH, the new unit has already become available for usage. The furnace was purchased with the help of OSW ManTech funding, while program management assistance was provided by NSWC Crane. From a purely mechanical standpoint, the main attraction of this piece of equipment is the capacity to heat materials up to 2400°C, as well as a sizable retort 28 in. in diameter and 30 in. tall with 8 cubic ft. of usable hot zone inside.

However, these specifications matter not only due to sheer capacity but also thanks to their fit for several of the required heat treatment stages. According to McNAIR, this system was developed specifically to help with pyrolysis, densification, and graphitization of aerospace composite parts and advanced ceramics. Notably, these are three distinct processes with their own specific features.

Specifically, pyrolysis entails heating of a sample in order to drive off volatiles and transform it into an initially carbon-rich structure, while densification serves to minimize porosity and increase the structural integrity of the material itself. On the other hand, the graphitization process is conducted on the higher side of temperature range and aims to transform carbon structure of the material further.

As per McNAIR’s announcement, this furnace is dedicated specifically to carbon-carbon, carbon-SiC, and SiC-SiC composites. This is an important detail for aerospace enthusiasts as this material list contains the type of materials used when regular metallic alloys run into either temperature or mass limitations. Carbon-carbon is still important for materials able to withstand extremely high temperatures, while carbon-SiC and SiC-SiC belong to the family of ceramic-matrix composites designed to offer lower density along with thermal and structural durability.

Along with temperature characteristics, process control is another crucial element for these types of materials. According to McNAIR, this furnace includes highly precise atmosphere and thermal settings, which is important for these kinds of materials due to the fact that their ultimate properties are determined by such factors as thermal conditions, atmosphere, duration of heat treatment, and even power input.

Thus, the importance of the integrated monitoring capabilities might be even greater as it allows engineers to analyze in real-time how changing pyrolysis, carbonization, or graphitization processes influence the properties of treated materials. From manufacturing perspective, this means a huge step forward as development of materials often stalls at the stage when researchers can heat a sample but do not possess sufficient knowledge of the way in which specific thermal and atmosphere settings influence the properties of materials produced in the furnace. Instrumented process monitoring allows narrowing down this gap.

However, this alone is not enough to produce certified materials or even develop a technology that could be employed in mass manufacturing. What this development adds, however, is better capability of working with advanced materials in a domestic setting as well as gaining valuable process insights that would allow scaling operations later on.

According to McNAIR, this furnace will be open for usage by industry and government partners for workforce development and training, contract manufacturing, process demonstration and validation, and advanced manufacturing scale-up initiatives. Notably, this combination of options usually determines the fate of material manufacturing processes as research and operator training conducted on the same hardware is an essential ingredient in developing industrial manufacturing practices.

Edward Collins – Senior editor for AMI’s performance systems and mechanical design content, with an emphasis on powertrains, drivetrain systems, manufacturing precision, materials, and high-performance engineering.