Advanced Solid Phase Processing Symposium: Advanced Friction Processing and Severe Plastic Deformation
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Mechanical Behavior of Materials Committee, TMS: Shaping and Forming Committee
Program Organizers: Suveen Mathaudhu, Colorado School of Mines; Cynthia Powell, Pacific Northwest National Laboratory; Kester Clarke, Los Alamos National Laboratory; Anthony Reynolds, University of South Carolina; Mostafa Hassani, Cornell University
Monday 8:00 AM
February 24, 2020
Room: Balboa
Location: Marriott Marquis Hotel
Session Chair: Suveen Mathaudhu, UC Riverside; Mageshwari Komarasamy, Pacific Northwest National Laboratory
8:00 AM Invited
Thermally Stable Nanostructured Immiscible Alloys via Friction Stir Processing: Rajiv Mishra1; 1University of North Texas
Friction stir processing (FSP) is a high temperature severe plastic deformation (HTSPD) method that can be used to process immiscible alloys. Forced mechanical mixing in the intense shear layer produces nanostructured features that are thermally stable. In this overview, the progress with Cu-based binary and ternary immiscible alloys have been reviewed. Remarkably, the Cu-Ag-Nb immiscible system displayed exceptional thermal stability up to 500ºC. Initial results show that the approach is amenable to manipulation of matrix and the Cu-Al-Nb system shows low stacking fault energy matrix with thermally stable nanostructures. Implications of these on the high temperature performance will be discussed. Solid state processing of such nanostructured alloys using FSP as HTSPD method opens a new domain not easily accessible by other processing techniques.
8:25 AM Invited
Linear Friction Welding of Ti Components:Iinvestigation of Residual Stress and Fatigue Performance: Ritwik Bandyopadhyay1; Michael Sangid1; 1Purdue University
Linear friction welding, of similar or dissimilar Ti alloys, offers a promising technology for producing large, net shaped components with assured or tailored properties. The residual stresses of Ti64-Ti64 and Ti64-Ti5553 welds are quantified via energy dispersive x-ray diffraction for the as-welded and post-weld heat treatment conditions, and the associated microstructures are analyzed by backscatter electron imaging. For these materials, fatigue failure is prone to occur in the Ti64 base material, which experiences anomalous fatigue behavior at high R ratios. To investigate this phenomenon, strain accumulation and crack initiation are investigated in various samples with and without microtextured regions via high-resolution digital image correlation and complemented with crystal plasticity modeling. In this work, the anomalous mean stress behavior experienced by Ti64 at high R ratios is explained by high creep sensitivity, activation of the pyramidal slip systems, and degree of micro-plasticity resulting in increased fatigue damage at high R ratios.
8:50 AM
Structure-Property Correlations in Friction Stir Welded 304L Stainless Steel: Madhumanti Bhattacharyya1; Arnab Kundu1; Indrajit Charit1; Krishnan Raja1; Jens Darsell2; Saumyadeep Jana2; 1University of Idaho; 2Pacific Northwest National Laboratory
Recently, applicability of friction stir welding (FSW) as a potential crack repair technique in stainless steel dry storage canisters has garnered much interest. The present work aims to explore the microstructure-mechanical property correlations in FSWed 304L stainless steel joints. FSW was carried out at two temperatures (725 and 825 °C) in order to repair simulated cracks created by electrical discharge machining in hot rolled-annealed stainless steel plates. A robust algorithm was used to maintain constant temperature during welding through tool RPM variation. Optical microscopy revealed the overall microstructural gradient across the weld. Microstructural examination using transmission electron microscopy revealed ultrafine grains (UFG) formed at the stir zone due to dynamic recrystallization during FSW. The UFG microstructure results in a significant increase in hardness within the stir zone compared to the base metal, as evaluated from Vickers microhardness testing. Further, residual stress distribution across the welds was evaluated using X-ray diffraction.
9:10 AM
Investigation of Metastable Structure Evolution in Friction Consolidation: Mageshwari Komarasamy1; Xiao Li1; Scott Whalen1; Glenn Grant1; 1Pacific Northwest National Laboratory
Significant evidence exists on the formation of extended solid solubility and metastable phases in alloys under severe plastic deformation (SPD) conditions. Friction consolidation is an SPD technique that imparts severe plastic strain at high temperature into the processed volume creating unique microstructures. In the current investigation, friction consolidation of powders and investigation of microstructural evolution using various microscopy techniques were carried out. Significant microstructural changes occurred in all the alloy combinations investigated. For instance, extreme structural refinement had occurred in Al-Si system while extended solubility and metastable phase formation were noted for Cu-Nb system. Overall, the ShAPE process is expected to have the potential to unlock unique combination of microstructures consisting of stable and metastable phases in various alloy systems.
9:30 AM
Joining Dissimilar Materials via Rotational Hammer Rivet Technique: Tianhao Wang1; Scott Whalen1; Woongjo Choi1; 1Pacific Northwest National Laboratory
A mechanically robust joining method for Al/Mg and Mg/CFRP enables decreased vehicle weight while offering more flexibility for vehicle designers. However, certain challenges exist for joining Al/Mg and Mg/CFRP. Mechanical joining cannot seal the dissimilar interfaces against corrosion. With solid-state and fusion based welding, rapid formation of brittle intermetallic compounds at the Al/Mg interface lead to interfacial fracture under mechanical loading. Large differences in physical and mechanical properties of metals and polymers make joining Al or Mg/CFRP challenging. In this study, a Rotational Hammer Rivet (RHR) technique was developed to fabricate Mg/CFRP and Al/Mg joints. Through heat generated by plastic deformation of an Mg rivet, RHR creates a metallurgical bond between rivet head and Mg sheet which seals corrosive electrolyte out of the joint. Direct joining between Al/Mg and Mg/CFRP were avoided. RHR tool design and process parameters were optimized based on microstructural and mechanical characterization of the dissimilar joints.
9:50 AM Break
10:10 AM Invited
Recent Developments in Upscaling High Pressure Torsion: Anton Hohenwarter1; Reinhard Pippan2; 1University of Leoben; 2Erich Schmid Institute of Materials Science, Austrian Academy of Sciences
High-pressure torsion (HPT) has advanced to one of the leading severe plastic deformation (SPD) techniques over the last several years. The processable materials are quite versatile ranging from pure metals, difficult to deform alloys and bulk metallic glasses. In addition, HPT is not restricted to bulk pre-cursor materials but also applicable to powders. The largest drawback of HPT is the relatively small sample size that impedes the implementation of the gathered knowledge about structure-property relationships on sample or component dimension that are interesting for industrial use. In this contribution advances in HPT processing are presented. Planar HPT (P–HPT) is capable of inducing large shear strains into materials with planar geometries, such as sheets or strips. Incremental HPT focuses on SPD of rod-like components. Both techniques will be introduced and some recent results on material synthesis studies are presented.
10:30 AM
Thermo-mechanical Processing of ZK Series Magnesium Alloys for Improved Low Temperature Performance: Guney Yapici1; 1Ozyegin University
This work shares the recent advances on the thermo-mechanical processing of a zinc-zirconium bearing magnesium alloy highlighting the artificial aging response. ZK60 alloy was subjected to warm rolling followed by aging, whereby the effect of external stress was evaluated in a comparative manner with conventional aging. The need for multi-step solid phase processing routes for enhanced strength and ductility is elaborated in light of the microstructural observations. Findings on the low temperature mechanical properties along with the implications on formability are discussed.
10:50 AM
Incremental Equal Channel Angular Pressing as a Tool for Manufacturing Large Ultra-fine Grained Copper Rods: Marta Ciemiorek1; Piotr Bartkowski1; Witold Chrominski2; Lech Olejnik1; Malgorzata Lewandowska1; 1Warsaw University Of Technology; 2Warsaw University of Technology
Incremental Equal Channel Angular Pressing makes it possible to process billet of significant dimensions (10 x 10 x 200 mm) as friction is reduced thanks to the fact that the plastic shearing is applied in small increments. This is achieved using a separated die set instead of one solid die, i.e. a forming and a clamping die that create an inlet channel and punch that moves up and down, deforming the processed rod in an outlet channel.Copper rods suitable for conductive structural components were acquired by I-ECAP after 8 passes. This resulted in the development of ultra-fine grained microstructure, increased the mechanical strength by around 60% in comparison to initial condition. After additional thermal processing, it was possible to achieve electrical conductivity equal to 94 %IACS, without significant deterioration in the mechanical strength. The shearing process was also modelled using FEM.
11:10 AM
Tailoring the Magnetic Properties of Nanostructured Alloys by Severe Plastic Deformation: Martin Stückler1; Lukas Weissitsch1; Stefan Wurster1; Heinz Krenn2; Andrea Bachmaier1; 1Erich Schmid Institute, Austrian Academy of Sciences; 2Institute of Physics, University of Graz
High-pressure torsion (HPT), a method of severe plastic deformation, is a top-down technique to obtain nanostructured bulk materials at high homogeneity. In addition, alloys with an extension of their equilibrium phases beyond their compositional range, can be generated. The principal is similar to mechanical alloying, however no sintering is necessary because one obtains a bulk sample. In this study, deformation-induced mixing is induced in different binary systems. SQUID-magnetometry revealed soft magnetic properties as well as contributions of thermal relaxation and frustration, which are disentangled with AC-mode measurements. The magnetic properties are further tuned by subsequent annealing treatments. Particular emphasis in this study is placed on the correlation of magnetic data with microstructural characterization with techniques of electron microscopy, synchrotron X-ray diffraction and atom probe tomography.