MEMS-based in situ electron-microscopy investigation of rapid solidification and heat treatment on eutectic Al-Cu

TL;DR

This study uses MEMS-based in situ STEM experiments to explore rapid solidification and heat treatment effects on eutectic Al-Cu, revealing diverse morphologies and spheroidization behavior relevant to industrial materials.

Contribution

It introduces a MEMS-based methodology for in situ STEM analysis of solidification in industrial-like Al-Cu alloys, enabling controlled rapid solidification and heat treatment observations.

Findings

Different rapid solidification morphologies achieved on a single specimen

Post-solidification heat treatment induces spheroidization of lamellas

Methodology simulates industrial processing conditions

Abstract

The solidification behavior of a eutectic AlCu specimen is investigated via in situ scanning transmission electron microscope (STEM) experiments. Solidification conditions are varied by imposing various cooling conditions via a micro-electro-mechanical system (MEMS) based membrane. The methodology allows the use of material processed by a melting and casting route close to industrial metallurgically fabricated material for in situ STEM solidification studies. Different rapid solidification morphologies could be obtained solely on a single specimen by the demonstrated strategy. Additional post-solidification heat treatments are investigated in terms of observation of spheroidization of lamellas during annealing at elevated temperatures.