Development of Light Weight Alloys and Composites : Microstructure and Processing: Composites II
Program Organizers: Ramasis Goswami, Naval Research Laboratory; Nikhil Gupta, New York University; Tanjore Jayaraman, United States Air Force Academy; Aashish Rohatgi, Pacific Northwest National Laboratory
Monday 2:00 PM
October 18, 2021
Room: A214
Location: Greater Columbus Convention Center
Session Chair: Nikhil Gupta, New York University, Tandon School of Engineering; Tanjore Jayaraman, College of Engineering and Computer Science, University of Michigan-Dearborn
2:00 PM Invited
Impact of Laser Shock Peening on Stress Corrosion Susceptibility in Al-Mg Alloys: Eric Dau1; William Golumbfskie2; Matthew McMahon2; 1Vision Point Systems, LLC.; 2Naval Surface Warfare Center, Carderock Division
Al-Mg alloys having Mg content greater than 3 wt.% are high performance materials for marine structural applications requiring exposure to aggressive saltwater conditions. The Mg content that affords high strength-to-weight ratio and weldability, however, also enables sensitization in service at temperatures exceeding 40 ᵒC, which causes increased susceptibility to intergranular stress corrosion cracking (IG-SCC). The laser shock peening (LSP) surface treatment is a candidate to reduce this susceptibility by imparting deep compressive residual stresses, however the efficacy of this process in reducing IG-SCC is relatively unknown. The present work compares the IG-SCC susceptibility of Al-Mg alloys having variations of LSP treatment through accelerated stress corrosion testing in simulated service conditions. Multiple combinations of LSP parameters were utilized to understand if a unique balance of treatment conditions exists to achieve a high level of IG-SCC mitigation.
2:40 PM Invited
Low Cycle Fatigue Behavior of Conventional High Temperature Titanium Alloys for Aeroengine Applications: Ramachandra Canumalla1; 1Vice President and Chief Technology Officer
Conventional high temperature Titanium alloys were developed and are evolving further for use at least up to 923K in aeroengine parts like compressor discs, shafts, blades and other parts to reduce weight and fuel consumption. Apart from the matrix bimodal and lamellar microstructures, fine structural changes like the precipitation of silicides and/or Ti3Al or both the phases, metastable β, martensitic crystal structure, dynamic strain aging, texture etc. affect the Low Cycle Fatigue (LCF) resistance of these conventional titanium alloys during service conditions. Two slope behavior in Coffin-Manson plot and the effect of hold and/or dwell period on LCF life have been highlighted. Further, environment on fatigue life has been discussed. These effects could have impact on the performance of the engine parts. Some observations from literature have been noted on the elimination of the two-slope behavior and other efforts to address other factors.
3:20 PM
Investigation of Microstructure, Interfaces and Mechanical Properties of Metal Matrix Composites: Ramasis Goswami1; 1Naval Research Laboratory
B4C is the lightest ceramic materials with the highest compressive strength. Considerable efforts have been made to enhance the specific strength of the composite by adding higher volume fractions of B4C particles in different metal matrices. It has been realized that the ceramic/metal interface plays a vital role in enhancing the strength of the composite materials. We investigate here using transmission electron microscopy (TEM) microstructure and interfaces of composite materials, such as Al/B4C and Fe/B4C, processed in the solid state at relatively high pressure, and correlate with the mechanical properties. We demonstrate that the interface cohesion and mechanical properties have been significantly improved as a result of the formation of metal boride at the interface. This provides a new avenue toward the development of composite materials containing B4C particulates.
3:40 PM Break
4:00 PM
Magnesium Alloy Composite with Metal Reinforced Particles Using Friction Stir Processing To Improve Mechanical Properties: Sangam Sangral1; Jayaprakash Murugesan1; Mahesh Patel1; Achyuth Kulkarni1; 1Indian Institute of Technology Indore
Owing to excessive environmental concerns and rising fuel cost, Magnesium alloy is the promising material of interest in automobile industry. In this study, the metallic powder (Nickel at diff. vol%) was employed as a reinforcement into AZ31 magnesium alloy (matrix) to form the metal matrix composite using friction stir processing. The microstructure characterization was done using an optical microscope and SEM. The tensile and fatigue behavior of the composites were also investigated in detail. From the results, the tensile strength of the composite was improved using reinforced particles and helped to retain significant ductility. The results obtained indicates a substantial improvement in the fatigue life of MMC as compared to the base material. Fretting is the major concern due to severe vibrations in most the automotive components. Fretting wear properties were evaluated using SEM equipped with EDS and surface profilometry.
4:20 PM
Inoculation of ML5 Cast Magnesium Alloy with Carbon Nano Powder: Spartak Makovskyi1; Vadym Shalomeev2; Volodymir Klochykhin1; 1Motor Sich JSC; 2National University Zaporozhye Polytechnica
A highly efficient cost-effective grain refinement technique for ML5 magnesium alloy with a commercially pure carbon nanopowder has been proposed. An experimental casting of testing specimens with incremental additions of a carbon nanopowder (0.001 - 0.1 wt.% ) was performed. It has been found that the carbon nanoparticle inoculation of the alloy structure is efficient in a narrow concentration range. The additions of 0.005-0.01 wt. % the grain refiner in the alloy resulted in a maximum increase of ductility properties (appr. twofold) and some improvement of the tensile strength. Further increase of the grain refiner content led to deterioration of the alloy mechanical properties. In particular, introduction of 0.1 wt.% of the nanocarbon and more caused formation of internal defects in the metal. The carbon nanoparticle inoculation is a promising way of improving the properties of the Mg-Al-Zn alloys for critical lightweight aerospace applications on industrial scale.
4:40 PM
Insights into Metal-based Polymer Pyrolysis for In-situ MMC Production: Aaron Gladstein1; Alan Taub1; 1University of Michigan
Metal matrix composites (MMCs) are of increasing importance to the transportation and aerospace industries as they allow for decreasing overall component weight without sacrificing mechanical properties, and in-situ MMCs offer further enhanced properties due to improved matrix-particle bonding and reduction in contamination as compared with ex-situ processes. This research focuses on MMCs made using metal-based polymer pyrolysis (MBPP), a process which creates polymer-derived ceramics (e.g. SiC) by thermally decomposing precursor polymers within the molten metal: once the bonds in the polymer break down, the elements in the polymer chain create ceramic particles. DSC-TGA was used to observe the steps in the conversion of the polymer. Tin-based MMCs were studied to compare the breakdown of the polymer in inert atmosphere and inside a melt. The morphology of the particles and their impact on microhardness was analyzed. The insights from the tin experiments were then applied to produce Al-based MMC’s.