Friction Stir Welding and Processing XII: Friction Stir Processing
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Shaping and Forming Committee
Program Organizers: Yuri Hovanski, Brigham Young University; Yutaka Sato, Tohoku University; Piyush Upadhyay, Pacific Northwest National Laboratory; Anton Naumov, Peter The Great St. Petersburg Polytechnic University; Nilesh Kumar, University of Alabama, Tuscaloosa
Monday 2:00 PM
March 20, 2023
Room: 29A
Location: SDCC
Session Chair: Nilesh Kumar, University of Alabama, Tuscaloosa; Hrishikesh Das, Pacific Northwest National Laboratory
2:00 PM
Enhanced Tensile and Tear Toughness Properties of Thin-wall Vacuum-assisted High-pressure Die-cast Aural-5 Alloy by Friction Stir Processing: Avik Samanta1; Hrishikesh Das1; Glenn Grant1; Saumyadeep Jana1; 1Pacific Northwest National Laboratory
Steadily rising demand for glider weight reduction has driven the development of vacuum-assisted high-pressure die-cast (HPDC) Al-alloys for automotive structural components. Aural-5 is a strontium-modified HPDC alloy utilizing manganese (Mn) to reduce die soldering, eliminating detrimental needle-shaped Fe-bearing β-phase intermetallic and improving ductility. HPDC Aural-5 contains shrinkage porosity, dendrites with Al-Si eutectic colonies, externally solidified crystals (ESCs), shear-band structure, and large second-phase particulates. Porosity, ESCs and large second-phase particles work as crack initiation sites, negatively impacting tensile properties. In this study, friction stir processing (FSP) is employed for microstructural modification of a thin-walled HPDC Aural-5 by eliminating porosity and breaking down dendrites, second-phase particles, eutectic colonies, ESCs and shear-band structures to create wrought microstructure with homogenized particle distribution. Mechanical property characterization indicates ~30% and ~35% enhancement in yield strength and ductility and associated marked effects on ~69% improvement in tear toughness according to the ASTM B871 test.
2:20 PM
Effect of Friction Stir Processing on the Microstructure and Mechanical Properties of Thick Al-6061 Alloy: Amlan Kar1; Eric Pickron1; Todd Curtis1; Bharat Jasthi1; Grant Crawford1; 1Arbegast Materials Processing and Joining Laboratory (AMP),
This paper highlights the influence of severe thermomechanical processing conditions on fabricating a high-strength and tough, 12 mm thick aluminum alloy (Al 6061-T6). An optimum thermomechanical condition using friction stir processing (FSP) technology produces a material with better tensile properties and a five-time increase in toughness. A detailed characterization reveals the evolution of refined microstructure with a good distribution of second-phase particles. The mechanism of microstructure evolution of aluminium is characterized as continuous dynamic recrystallization. Grain size and microhardness variation from the surface to the bottom of the processed zone is examined and correlated with processing conditions to identify the mechanisms of microstructural evolution. The improved tensile strength and toughness of the processed zone are attributed to lower heat input, grain refinement and location of fracture during testing of the developed material.
2:40 PM
Effect of Microstructure on Mechanical Properties of Friction Stir Processed Al Alloy: Rajashekara Sarvesha1; David Garcia2; Richard Eberheim3; Kenneth Ross2; Arvind Agarwal1; Tanaji Paul1; 1FIU College of Engineering and Computing; 2Pacific Northwest National Laboratory; 3Solvus Global
Friction stir processing (FSP) is a thermo-mechanical treatment that engenders gradient microstructure in the material. The present work elucidates the effect of microstructure in-homogeneity on the mechanical properties of a conventional non-heat-treatable Al5083 alloy. The mechanical properties were evaluated by a high-throughput profilometry-based indentation method. The variation in properties was related to grain size and dislocation density captured through high-resolution orientation imaging microscopy. Notably, a marginal variation in the properties resulted in strain partitioning between different zones and eventually fracture during external loading. Finally, different FSP strategies were employed to enhance the overall mechanical properties will be discussed.
3:00 PM
Surface Alloying Due to WC Tool Wear during FSP and Its Effects on the Microstructure and Mechanical Properties of Topmost Steel Layer: Hajime Yamamoto1; Yudai Imagawa1; Yuji Yamamoto1; Kazuhiro Ito1; 1Joining and Welding Research Institute, Osaka University
Friction stir processing (FSP) is a solid state method for surface modification using a rotational tool. However, the tool wear has been considered as the unavoidable issue in FSP of high strength materials. On the other hand, we found that the WC tool wear in low-carbon steels caused alloying of the topmost steel layer with the tool constituent elements. Some of the WC particles in the tool reacted with the Fe atoms to form Fe4W2C phase at the tool/steel interface during FSP, followed by fragmentation and decomposition due to shear stress. The austenitized topmost steel layer transformed to the martensite with supersaturated W and C atoms during the cooling time. With increasing the W and C contents, compressive residual stress was generated in addition to solid solution hardening. The unique alloying indicates positive utilization of the tool wear during FSP as a new line of thought.
3:20 PM Break
3:40 PM
Graphite-Reinforced 6201 Aluminum Alloy Fabricated by In-situ Friction Stir Processing: Process, Microstructure and Mechanical/Electrical Properties: Yijun Liu1; Gaoqiang Chen1; Fangzheng Shi1; Mengran Zhou1; Shuai Zhang1; Gong Zhang1; Qingyu Shi1; 1Tsinghua University
Friction stir processing (FSP) has proved to be successful in the past two decades for the preparation of novel metal matrix composites with preferable properties. In this work, graphite was added into 6201 aluminum alloy through multi-pass in-situ FSP in order to fabricate graphite-reinforced 6201 aluminum alloy. We look into the microstructure, the mechanical and electrical properties of the composites. It is found that, after multi-pass FSP, the graphite is significantly fragmented and uniformly distributed in the aluminum matrix. The tensile strength and electrical conductivity of the composites with 9-pass FSP are improved by 19.5% and 1.2% in comparison to the matrix. The number of FSP passes is an important parameter affecting the microstructure of the composites. Effect of the number of FSP passes on the tensile strength and electrical conductivity of the composites is investigated.
4:00 PM
Fabrication and Characterization of Mono and Hybrid Composites Using Friction Stir Processing with Soda-lime Glass and Polymer Reinforcements: Ankita Mohanty1; Nishkarsh Srivastava1; Mo Rizwan Qureshi1; Amit Arora1; 1Indian Institute of Technology Gandhinagar
Surface composites exhibit superior mechanical, tribological, and electrochemical properties compared to unreinforced alloys. These are achieved by incorporating one or more reinforcement elements into the parent material or the matrix. Therefore, in this work, we produce novel hybrid composites by incorporating soda-lime glass (SLG) and polyethene terephthalate (PET) reinforcements into the Al 1050 using friction stir processing (FSP). The influence of different tool rotational speeds and reinforcement types on the microstructure, particle distribution, and mechanical characteristics, including the surface composites' hardness, wear and electrochemical behaviour, have been studied. The results revealed a homogeneous distribution of particles in the stir zone at higher tool rotational speeds with no intermetallic formation in the surface composites. The hybrid composite showed the best hardness and wear properties. The addition of glass particles induced galvanic coupling in the surface composites, whereas PET-reinforced surface composites show the highest corrosion resistance.