Solid State Diffusion Bonding of Metals and Alloys: Poster Session
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Advanced Characterization, Testing, and Simulation Committee
Program Organizers: Mohamed Elbakhshwan, University of Wisconsin Madison; Mark Anderson, University of Wisconsin Madison; Todd Allen, University of Michigan ; Tasnim Hassan, North Carolina State University
Tuesday 5:30 PM
February 25, 2020
Room: Sails Pavilion
Location: San Diego Convention Ctr
Session Chair: Mohamed Elbakhshwan, UW-Madison; Heramb Mahajan, North Carolina State University
O-49: Joining of 14YWT Ferritic ODS Alloys by Spark Plasma Technique: Madhavan Radhakrishnan1; Elisa Torresani2; Eugene Olevsky2; Stuart Maloy3; Osman Anderoglu1; 1University of New Mexico; 2San Diego State University; 3Los Alamos National Laboratory
Nanostructured ferritic ODS alloys are promising candidates for fuel cladding applications due to their stable microstructure, strength and radiation tolerance at high temperatures. Here, spark plasma joining of as-rolled nanostructured 14YWT ferritic ODS alloys have been carried out at 800°C, 1020°C and 1030°C under a uniaxial pressure of 40 MPa. Samples bonded at 1030°C showed better chemical bonding with homogeneous microstructure across the interface, without any reduction in the hardness values compared to the base alloys. Density measurements indicate that samples joined at 1030°C are 98.6% dense, with some micro-voids trapped at the interface. The samples joined at 800°C yielded an incomplete bond with micro-cracks that runs along the entire sample. The presence of columnar grains continuously near the interface suggests the possibility of localized melting and subsequent solidification of the alloy as a result of local temperature rise that could be attributed to high contact resistance at the interface.
O-50: Optimization and Prediction of Bond Characteristics of Ti6Al4V Diffusion Bonded Joints through RSM: Pragatheswaran T1; Rajakumar S1; Balasubramanian V1; Vijay Petley2; Shweta Verma2; 1Annamalai University; 2Gas Turbine Research Establishment
In the aero engine components such as gas/jet turbine parts, Ti alloys are widely incorporated except some parts which are made by nickel base super alloys. Joining Ti components one with the other can be achieved by diffusion bonding technique. In this investigation, thin sheet of Ti6Al4V alloy which is having a thickness of 2 mm are diffusion bonded with the aim of analyzing the sensitivity of each process parameter on the bonding characteristics. Using response surface methodology (RSM), empirical relationships were established to predict the Ti6Al4V bond characteristics. Three factor 3 level central composite design matrix consists of 15 runs was obtained from Design Experts software. The responses such as shear strength, bonding strength and hardness were evaluated, analyzed numerically and graphically. From the sensitivity analysis, bonding temperature is found to be more influencing factor followed by bonding pressure and holding time.Keywords: Diffusion, Titanium, Design, Sensitivity, Strength, Hardness
Cancelled
O-51: Solid State Diffusion Bonding of ODS Eurofer Steel by Spark Plasma Sintering: Jia Fu1; J.C. Brouwer1; I.M. Richardson1; M.J.M. Hermans1; 1Delft University of Technology
Oxide dispersion strengthened (ODS) steels are considered to be one of the candidate structural materials for advanced nuclear applications due to their high elevated-temperature strength, corrosion resistance and radiation tolerance. Joining of ODS steels by traditional fusion joining techniques is not applicable, because the melting process results in the coarsening of fine grains and agglomeration of nanosized oxide particles, and consequently a significant loss of strength. Spark plasma sintering (SPS) has recently been employed as a novel joining technique, which could be beneficial for joining ODS steels considering the solid state characteristic. A powder metallurgy prepared ODS Eurofer steel was successfully joined using SPS. The microstructure and mechanical properties of the joints were investigated. An almost defect-free joint was obtained at the selected processing condition. The tensile properties of the joints are comparable to the base material. Fracture analysis shows an intergranular fracture in the as-joined sample, while a ductile fracture with well-defined dimples is found in the tempered sample.