Origins of Non-random Particle Distributions and Implications to Abnormal Grain Growth in an Al-3.5 Wt Pct Cu Alloy

The mechanisms of abnormal grain growth (AGG) in particle-containing systems have long been a mystery. Recently, we reported that a non-random particle distribution can induce a grain size advantage and trigger AGG. However, the processing conditions leading to a non-random particle distribution are...

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Bibliographic Details
Published in:Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2021-03, Vol.52 (3), p.914-927
Main Authors: Lu, Ning, Kang, Jiwoong, Shahani, Ashwin J.
Format: Article
Language:English
Subjects:
Aluminum
Characterization and Evaluation of Materials
Chemistry and Materials Science
Copper
Copper base alloys
Grain growth
Grain size
High temperature
Inhomogeneity
Materials Science
Mathematical analysis
Metallic Materials
Nanotechnology
Original Research Article
Phase distribution
Structural Materials
Surfaces and Interfaces
Temperature
Thin Films
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Summary:The mechanisms of abnormal grain growth (AGG) in particle-containing systems have long been a mystery. Recently, we reported that a non-random particle distribution can induce a grain size advantage and trigger AGG. However, the processing conditions leading to a non-random particle distribution are far from being understood. Here, we investigate the particle distribution and concomitant grain growth behavior at different annealing temperatures and times in an Al-3.5 wt pct Cu alloy by scanning electron microscopy (SEM). At high temperatures and long times, the particle distribution evolves from random to non-random, with an accompanying transition from normal grain growth (NGG) to AGG. Analytical calculations suggest that a non-random particle distribution is introduced by residual Cu segregation even after homogenization. In short, the corresponding fluctuation of θ -Al 2 Cu phase distribution is amplified at elevated temperatures via particle dissolution. We quantify the spatial inhomogeneity of particles through the Gini coefficient and link this important parameter to the critical grain size necessary for AGG. The trends are conveyed succinctly in a temperature–time–(structural) transformation (TTT) diagram, which identifies the onset of AGG in an Al-3.5 wt pct Cu alloy.
ISSN:1073-5623
1543-1940
DOI:10.1007/s11661-020-06125-0