Verification Programme
To demonstrate how overaged (i.e. "engine-run") microstructures can be recovered to the "as-new" condition using E&CT Recovery heat treatments.
Verification Programme Overview
Data will be presented from
stress rupture testing and
microstructural analysis carried out on "as-new" overaged and "recovered" samples.
Stress Rupture Testing

A furnace chamber surrounds each specimen keeping the samples at a constant temperature.
The test runs until the sample ruptures. The hours to rupture are recorded. This gives an indication of the strength of the material.
Summary of Stress Rupture Testing Results
Values obtained clearly demonstrated that Marm-002 EA and DS overaged material was fully recovered back to the ‘as-new’ condition.
Microstructural Analysis - Overaged Material

Overaged DS and EA materials were confirmed to have heavily degraded microstructures comprising the following features:
- Gamma prime coarsening and agglomerisation.
- Increased spacing between gamma prime precipitates.
Microstructural Analysis - Recovered Condition

The microstructures of the DS and EA materials were found to be similar to that os "as-new" material. They comprised the following features:
- Ordered gamma primed islands/colonies
- Spacing decreased between gamma prime precipitates
Conclusions
Stress Rupture Testing
Values obtained clearly demonstrated that Marm-002 EA and DS overaged material was fully recovered back to the ‘as-new’ condition using RWG proprietary heat treatments.
Microstructural Analysis
Optical and Scanning Electron Microscopy demonstrated that ‘overaged’ EA and DS microstructures were fully recovered back to the ‘as-new’ condition.