Additive Manufacturing: Materials Design and Alloy Development IV: Rapid Development: On-Demand Poster Session
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee, TMS: Integrated Computational Materials Engineering Committee
Program Organizers: Behrang Poorganji, University of Toledo; Hunter Martin, HRL Laboratories LLC; James Saal, Citrine Informatics; Orlando Rios, University of Tennessee; Atieh Moridi, Cornell University; Jiadong Gong, Questek Innovations LLC

Monday 8:00 AM
March 14, 2022
Room: Additive Technologies
Location: On-Demand Poster Hall

A 3-D Multiple-slip Crystal Plasticity Model for Precipitate Hardening in Additively Manufactured High Strength Steels: Moustafa AbdelHamid1; Tarek Hatem2; 1Nile University; 2The British University in Egypt
    Additive Manufacturing (AM) revolutionized the manufacturing of complex geometry products, especially in medical and aerospace fields. High-strength precipitate hardened (PH) stainless steels provide unique properties in term-of strength and corrosion resistance for critical applications in both fields. In the current study, a 3D multiple-slip crystal-plasticity dislocation-densities based model is used to study the effect of copper precipitate hardening in high-strength stainless steels. The proposed approach accurately predicts the complex structure of martensite and properly represents the precipitates, based on its characteristics, such as: texture, morphology, secondary phases and initial-dislocations-densities. The results show the effect of materials’ characteristics on mechanical properties and failure of AM-PH high-strength steels. The current work lays the groundwork for more extensive work of AM modeling.

Analysis on Solidification Microstructure and Cracking Mechanism of a Matrix High-speed Steel Deposited by Direct Energy Deposition Process: Geon-Woo Park1; Sunmi Shin1; Byung Jun Kim1; Wookjin Lee2; Sung Soo Park3; Jong Bae Jeon4; 1Korea Institute of Industrial Tehcnology; 2Pusan National University; 3Ulsan National Institute of Science and Technology; 4Dong-A University
    We investigated microstructure and cracking mechanism of a matrix high-speed steel fabricated by direct energy deposition. It was attempted to analyze combined effect of rapid solidification and chemical composition on microstructure and cracking mechanism during deposition. Excessive solute segregation into inter-dendritic regions due to rapid solidification gave rise to the formation of retained austenite in the inter-dendritic region and the formation of α'-martensite in the dendritic region, respectively. The excess solute segregation decreased equilibrium solidification temperature and caused precipitation of the low-melting eutectic carbides in the inter-dendritic region. The low-melting eutectic carbides increased hot cracking susceptibility resulting in solidification cracking and liquation cracking in the inter-dendritic region. On the other hand, tensile residual stress in deposited layers generated due to constraint by substrate possibly caused cold cracking in α'-martensite. It was revealed that the cold cracks led to macro-crack growth by connecting the ligaments between hot cracks in deposited layers.

Ceramic–metal Composites Using Ceramic 3D Printing and Centrifugal Infiltration: Shahbaz Khan1; Ling Li1; 1Virginia Tech
    The study of natural materials has enabled mankind with principles for the design of novel composite materials. In this work, we use stereolithographic 3D printing of ceramic preforms which are, post-sintering, infiltrated with aluminum alloy using centrifugal infiltration to produce 2D and 3D interpenetrating composites inspired by the prismatic layers of bivalve molluscan shells. The proposed method provides flexibility in the design of individual composite phases and advantages in terms of scalability. The specific compressive strength of composites was recorded to be as high as 169% the specific compressive strength of the monolithic aluminum alloy. Additionally, the highest fracture toughness was measured to be 12.9 MPa m1/2. Toughening mechanisms such as ductile phase deformation, ceramic confinement and crack deflection at interfaces were observed. The porosity in the ceramic phase, measured using tomographic structural analysis, was found to be 15% and it is believed that the performance of composites may further be improved by reducing defects and porosity in the ceramic phase.

In-situ Alloying of Ti-Zr-Nb-Sn Bio-titanium Alloys via Direct Energy Deposition: Yukyeong Lee1; Jonghyun Jeong1; Eun Sung Kim2; Shuanglei Li1; Jae Bok Seol1; Hyokyung Sung1; Hyoung Seop Kim2; Taehyun Nam1; Jung Gi Kim1; 1Gyeongsang National University; 2Pohang University of Science and Technology
    A combination of high energy laser and powder feeding control in DED machine allows to enable a rapid alloy prototyping strategy that expands the alloy design window by additive manufacturing. However, different characters of elemental powders make a difficulty to get an optimal processing condition for rapid alloy prototyping that results into the non-homogeneous matrix. Therefore, complete melting and mixing of elemental powders to obtain a homogeneous matrix during AM can be a challengeable issue. In this study, Ti-Nb-Zr-Sn bio-titanium alloys are designed by adapting rapid alloy prototyping strategy using Ti, Zr, Nb, and Sn elemental powders. Microstructure analysis and tensile tests were performed to confirm the compositional homogeneity and mechanical properties of the Ti-Nb-Zr-Sn alloys fabricated through rapid alloy prototyping, and the correlation between the microstructure and mechanical properties will be discussed.