On the Rapid Assessment of Mechanical Behavior of a Prototype Nickel-Based Superalloy using Small-Scale Testing

Sabin Sulzer,Bryan Roebuck,André Németh,Roger Reed,Enrique Alabort

doi:10.1007/s11661-018-4673-5

Sabin Sulzer, Bryan Roebuck + Show 3 more

Open Access

https://doi.org/10.1007/s11661-018-4673-5

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Abstract

An electro-thermal mechanical testing (ETMT) system is used to assess the mechanical behavior of a prototype single-crystal superalloy suitable for industrial gas turbine applications. Miniaturized testpieces of a few mm2 cross section are used, allowing relatively small volumes to be tested. Novel methods involving temperature ramping and stress relaxation are employed, with the quantitative data measured and then compared to conventional methods. Advantages and limitations of the ETMT system are identified; particularly for the rapid assessment of prototype alloys prior to scale-up to pilot-scale quantities, it is concluded that some significant benefits emerge.

Highlights

NEW alloy grades are never deployed without careful testing of their properties and performance under conditions close to those experienced in service
Tensile curves at 500 °C are shown in Figure 5; comparison is made with duplicate tests on the National Physical Laboratory (NPL) electro-thermal mechanical testing (ETMT) system
Results from both ETMT systems are in good agreement for all orientations, but values of engineering stress in the plastic regime for the h011i and h111i directions are slightly higher in the NPL tests

Summary

Introduction

NEW alloy grades are never deployed without careful testing of their properties and performance under conditions close to those experienced in service Such so-called qualification activities can be difficult and costly; this explains why the time needed to insert them into new applications can be notoriously long.[1,2,3] processing costs for the production of pilot-scale material quantities can be excessively large—often too great to justify— leading to conservatism and undue emphasis on maintaining the status quo. Without a doubt, such challenges lead to a slackening in the pace of technological change.

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