Material Development for Near-Net-Shape Automated Manufacturing of Composite Structures for Ultra Hi
Abstract
ONR Program Manager: Dr. Anisur Rahman Airframe Structures and Materials (Code 35)Carbon-carbon composites or carbon fiber reinforce,d carbon (CFRC) are used for various ultra-high temperature applications such as reentry vehicles and ballistic missiles as well as,for high performance Formula One race car brake discs and brake pads. CFRC is used in areas such as rocket nozzles and wing leading, edges of reentry vehicles where low coefficient of thermal expansion (CTE) and thermal shock resistance are needed. Compared to pol,ycrystalline (monolithic) carbon, reinforced carbon has significantly improved stiffness, strength (tensile), and fracture toughness, properties. Although carbon-carbon materials have excellent thermostability, high thermal conductivity, and low CTE, they are extre,mely brittle and have low impact resistance. In order to improve the damage tolerance (impact resistance and brittle fracture), the,CFRC is typically reinforced with woven fibers through-the-thickness. Thus,the high-performance CRFCs are produced as a laborious an,d costly three-dimensional woven billet and machined to the final shape similar to substrative metal machining. The extremely high c,ost and time-consuming process make it prohibitively expensive for standard aerospace applications. During the manufacturing process, of CFRC, carbon fibers are impregnated with an organic resin/binder with added carbon aggregate and pyrolyzed at high heat converti,ng the bonder to relatively pure carbon. During the pyrolysis, the binder loses volume forming voids. In order to fill the voids, th,e material is impregnated with more binder several times followed by pyrolysis or infused with carbon-forming gas at high temperatur,es over several days until the targeted material properties are achieved. The primary goal of the proposed program is to investigate, the use of standard prepreg (polymer-matrix composites) with automated fiber placement for laying up a near-net-shape followed by p,yrolysis for reducing the overall cost and increase manufacturing rates. This process eliminates the substrative machining process o,f extremely expensive 3D-woven CFRC resulting significant cost saving on materials and processing time. With the proposed equipment,, standard prepreg material will be customized to improve the post-AFP pyrolysis by tailoring the resin chemistry by removing unneces,sary chemical compounds (that will be burnt off during pyrolysis) and by adding carbon aggregates to the binder to reduce the void f,ormation. This abstract is publicly releasable.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 13, 2022
- Source ID
- N000142212611
Entities
People
- Waruna Seneviratne
Organizations
- Office of Naval Research
- United States Navy
- Wichita State University