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MM: Fachverband Metall- und Materialphysik

MM 16: Microstructure and Phase Transformations III - Precipitaion hardening/ Alloying elements

MM 16.1: Vortrag

Montag, 31. März 2014, 15:45–16:00, IFW B

Atom Probe Tomography Analyses of Precipitation in the AA2195 Aluminum Lithium Alloy — •Muna Khushaim¹, Torben Boll¹, Ferdinand Haider², and Talaat Al-Kassab¹ — ¹King Abdullah University of Science and Technology (KAUST), Division of Physical Sciences and Engineering, Thuwal 23955-6900. Saudi Arabia — ²University Augsburg, Inst. f. Physik, D-86159 Augsburg, Germany

One of the primary materials used for structural components of aircrafts are aluminum-lithium alloys. These alloys exhibit an enhanced strength-weight ratio which makes them an attractive material for weight critical applications. This study focuses on the alloy 2195 (a member of a series of high strength Al-Li-Cu alloys known as Weldalite), which owes its superior mechanical properties to a thermo-mechanical treatment termed T8. The presence of different micro-alloying elements and an adequate heat treatment causes the precipitation of different phases such as T₁ (Al₂CuLi), θ′(Al₂Cu) and β′(Al₃Zr). Utilizing the laser assisted wide angle tomographic atom probe (LAWATAP) and local electrode atom probe (LEAP) allowed the characterization of the different precipitates that dominate the microstructure of this functional material and identify their role in the hardening process. Additionally, the effect of the microstructure on the mechanical properties of the alloy was estimated by measuring its micro-hardness.