The contribution of small punch testing towards the development of materials for aero-engine applications

Roger C Hurst,Robert J Lancaster,Spencer P Jeffs,Martin R Bache

doi:10.1016/j.tafmec.2016.07.013

Roger C Hurst, Robert J Lancaster + Show 2 more

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https://doi.org/10.1016/j.tafmec.2016.07.013

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Abstract

This paper, invited for presentation at the 33rd Meeting of the Spanish Group on Fracture and Structural Integrity, March 2016 in San Sebastian, Spain, reviews the recent work carried out in the authors’ laboratory, addressing the elucidation of tensile and creep characteristics of materials for aero engine components. Two specific applications of the Small Punch (SP) test assessment technology were identified, the first of these takes on board the unique potential of the SP test for testing small quantities of materials which are either in development or through their directional structure cannot easily be produced in quantities which would allow conventional mechanical testing. This goal also required the development and procurement of new SP test facilities capable of operation up to 1150°C. The examples given in this paper are TiAl intermetallic alloys and nickel based single crystals, all studied utilising the Code of Practice for SP Creep Testing. The second application illustrates the use of SP testing to assess both the tensile and creep properties of additive layer manufactured (ALM) alloys such as IN718 and Ti-6Al-4V using the Code of Practice for SP Tensile and Fracture Testing. Due to the unavailability of sufficient material to facilitate conventional testing for comparison of materials property data, SP testing is unable to provide absolute data for all of these applications, nevertheless the ranking capabilities of SP testing are demonstrably proven.

Highlights

In the 1980s the original intention of the Small Punch Test was to assess the degradation of nuclear reactor components as a result of irradiation damage [1,2]
The aero-engine community have recognised the unique potential of the small punch (SP) creep test for testing small quantities of novel candidate materials which cannot be produced in quantities which would allow significant conventional mechanical testing due to prohibitive cost
The alloy selected was the established turbine blade alloy CMSX-4Ò,1 tested at elevated temperatures of 950 °C, 1050 °C and 1150 °C

Summary

Introduction

In the 1980s the original intention of the Small Punch Test was to assess the degradation of nuclear reactor components as a result of irradiation damage [1,2] This was mainly aimed at determining tensile and fracture properties of the reactor pressure vessel steels [3,4]. A decade later the technique was encouraged for application to study the degradation due to creep of conventional fossil fuel fired energy plant components [5] For these two types of applications, a European Code of Practice (EUCoP) for SP tensile, fracture and creep testing was developed early in the 21st century and launched by CEN in 2006, revised in 2007 [6].

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