UNCLASSIFIED Titanium Diboride Reinforced Boron Carbide Azmi M. Celik, Dr. Chawon Hwang, Dr. Vladislav Domnich, Dr. Atta Ullah Khan, Dr. Richard A. Haber Enterprise for Mul/-scale Research of Materials Rutgers, The State University of New Jersey How We Fit Major Results Major Results (Continued) Materials-by-Design Process Mechanism-based Approach Microstructure Evaluation & Vickers Hardness (HP) Crack Propagation Behavior (SPS) B4C TiB2 B4C crack branching intergranular transgranular 1/2 Sample Hv(1kg), GPa Std. dev. KIc, MPa.m Std. dev. Monolithic B4C 30.03 1.50 2.30 0.19 B4C + 10wt%TiB2 32.92 1.47 2.77 0.51 Spark Plasma Sintering Conditions: 1950ºC, 5 minutes, 50 MPa Grain size: ~10-20 µm TiB addition inhibits the grain growth of B C Key Goals 2 4 Key Accomplishments B4C+10wt% TiB2 • Improve mechanical properties and investigate toughening • Composites with improved toughness were produced mechanisms of boron carbide-titanium diboride composites • Hot press was utilized to fabricate large samples (up to ø6”) • Fabricate industry-scale samples via Hot Press • Grain growth in B4C was suppressed by TiB2 addition (HP) Technical Approach Transitions to ARL, within TiB2 B4C CMRG and to other CMRGs To improve its resistance to crack propagation, boron • Ballistic impact tests on hot pressed plates to investigate carbide (B4C) was reinforced with titanium diboride (TiB2). ballistic performance (ARL) Spark plasma sintering was utilized in preliminary work to • Kolsky bar expt. to examine fracture and fragmentation (JHU) investigate microstructure and crack propagation behavior. B4C Grain size: ~1-2 µm The most promising composition (B4C + 10wt%TiB2) was B4C Impact hot pressed to examine feasibility of large-scale production. B C+TiB Hot Pressed B4C-10 wt% TiB2 (ø4”) 4 2 • Fundamental research can help understanding and engineering • Optimize sintering conditions to achieve full densification new composite microstructures to achieve improved material via Spark plasma sintering (SPS) and Hot press (HP) properties such as hardness, toughness, and Young’s modulus • Identify the mechanisms of improvement in hardness Hv(GPa) • Materials with engineered microstructures can be fabricated in and toughness of B C by TiB incorporation 4 2 large-scale via hot press for possible ballistic applications Hot Pressing Conditions: 2150ºC, 4.5 hr, 24 MPa ρ = 2.64 g/cm3 (>99.9%) Load (kg) UNCLASSIFIED .