Abstract
The hot-tearing resistance of multicomponent Al-Cu alloys during permanent mold casting was investigated using a constrained permanent mold in which the load and temperature were measured. The nominal Cu composition was varied from 5 to 8 wt pct. Casting experiments were conducted without adding any grain-refining inoculants. The following variables, which were obtained from the measured load data during casting, were considered to assess the hot-tearing resistance of the Al-Cu multicomponent alloys: “V”-like signature in the load rate variation, load at solidus point, and load rate average over the freezing range. In addition, a hot-tearing criterion based on the variation of the fraction of solid in the late stages of solidification was used. It was found that all criteria considered can accurately predict the alloys with the lowest and highest hot-tear resistance, respectively. It was found that the rate of measured load during casting could be used to indicate substantial hot tearing. However, the load rate variation could not be used to detect when small hot tears were present. Among all the criteria considered, the load at the solidus point shows an excellent agreement with experimentally observed hot-tearing resistance for all but one alloy. The poorly resistant hot-tearing alloys exhibited mainly coarse columnar grains while the most hot-tearing resistant alloys exhibited a much more refined grain microstructure. This is the first study in which good hot-tear resistance is demonstrated for multicomponent Al-Cu alloys with nominal Cu content greater than 7 wt pct.
| Original language | English |
|---|---|
| Pages (from-to) | 1267-1287 |
| Number of pages | 21 |
| Journal | Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science |
| Volume | 49 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jun 1 2018 |
Funding
This work was performed under a Cooperative Research and Development Agreement (CRADA) with Nemak Inc., and FCA US LLC for the project ‘‘High Performance Cast Aluminum Alloys for Next Generation Passenger Vehicle Engines.’’ Research was sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office, as part of the Propulsion Materials Program under contract DE-AC05-00OR22725 with UT-Battelle, LLC. The authors would like to thank Tom Geer and Dana R. McClurg of ORNL for metallographic specimen preparation. This submission was sponsored by a contractor of the United States Government under contract DE-AC05-00OR22725 with the United States Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). Manuscript submitted June 21, 2017. Article published online February 16, 2018.
| Funders | Funder number |
|---|---|
| U. S. Department of Energy | |
| United States Department of Energy | |
| Office of Energy Efficiency and Renewable Energy | DE-AC05-00OR22725 |