Active Clearance Control tuning through Coefficient of Thermal Expansion (A-tu-C)

Purpose and goal:

A-tu-C Project assessed CTE of 3 plate types with 2 HTs. Studied repeats, scan rate, sample length, HT steps effect and data from 3 labs. The project goals are achieved.

Experimental efforts with detailed microstructure analysis with modelling have contributed to 1) increased understanding of variations in CTE for Haynes® 282® and controlling features 2) developed a framework for thermodynamic modelling of CTE with preliminary validation. Indications propose possibility to modify Haynes® 282® CTE to replicate Waspaloy.

Expected results and effects:

CTE performed on >30 samples. Variation in repeats is 1%; HT steps ~ 1.5%, scan rate, sample size, plates ~ 2.5% and between labs > 3%. Modelling yielded preliminary framework for CALPHAD-based calculations of Haynes® 282® CTE, including thermodynamic CTE calculations of individual phase compositions leading to superalloy CTE model.

This is calibrated with brochure, validated against data generated. Then evaluated effect of composition variations within specification and potential heat treatment modifications. Approach and implementation:

GKN handled project coordination in WP0. The CTE modelling was performed by KTH and QuesTek Europe in WP1 through close collaboration. KTH focused on phase-level CTE descriptions, phase composition and stability through CALPHAD, QuesTek focused on framework development and calibration to experimental data.

Experimental CTE measurements and microstructural analysis was conducted by Jönköping University in WP2. Recurring information exchange within WPs ensured that relevant data was generated experimentally and computationally, and the understanding on CTE increased.