TASK 70-02-10-220-501 IAE 1422 Microstructure For Metal Temperature Analysis

DMC:V2500-00-70-02-10-00A-350A-D|Issue No:001.00|Issue Date:2013-11-01

Export Control

EAR Export Classification: Not subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3), except for the following Service Bulletins which are currently published as EAR Export Classification 9E991: SBE70-0992, SBE72-0483, SBE72-0580, SBE72-0588, SBE72-0640, SBE73-0209, SBE80-0024 and SBE80-0025.

Copyright

© IAE International Aero Engines AG (2001, 2014 - 2021) The information contained in this document is the property of © IAE International Aero Engines AG and may not be copied or used for any purpose other than that for which it is supplied without the express written authority of © IAE International Aero Engines AG. (This does not preclude use by engine and aircraft operators for normal instructional, maintenance or overhaul purposes.).

Applicability

All

Common Information

TASK 70-02-10-220-501 IAE 1422 Microstructure For Metal Temperature Analysis

General

NOTE

This Metal Temperature Analysis can be used to analyze IAE 1426 blades.

Refer to the SPM TASK 70-02-03-220-501 for the procedure to do a metal temperature analysis on nickel base alloys.

IAE 1422 is the specification for nickel-base, 9.0 percent chromium, 10.0 percent cobalt, 12.0 percent tungsten, 1 percent columbium (niobium), 2.0 percent titanium, 5.0 percent aluminum, 1.6 percent hafnium, 0.015 percent boron, vacuum melted, directionally-solidified investment casting. The microstructure standards for the heat treated and coated alloy are contained in separate paragraphs in this section.

The microstructure of the blade root or shroud sections is not affected due to the relatively low metal temperature obtained during engine operation. This microstructure supplies an optimum baseline for comparison with the airfoil hot zone for metal temperature determination.

Figure shows typical microstructure below 2000 deg F (1093 deg C) of IAE 1422 DS nickel base alloy, which is:

Heat treated at 2210 to 2270 deg F (1210 to 1243 deg C).

Cooled to below 1200 deg F (649 deg C) at a rate equivalent to air cool or faster.

Heated to 1950 to 2000 deg F (1066 to 1094 deg F) for four hours and cooled at a rate equivalent to air cool or faster.

Precipitation Heat Treated at 1575 to 1625 deg F (857 to 885 deg C) for 32 hours and air cooled.

The typical microstructure of this fully heat treated super-alloy is characterized by a duplex array of gamma prime precipitate (Ni3Al,Ti) in a gamma matrix (nickel base solid solution). See Figure. This array consists of:

A fine, regularly spaced, quasi-rectangular gamma prime precipitate in dendritic arms.

A somewhat coarser gamma prime precipitate bordering the periphery of eutectic gamma prime islands which are located at interdendritic regions.

Grain boundaries

Also two types of MC carbides:

HfC and (45Ti, 35Nb, W, Hf)C, generally associated with eutectic gamma prime.

M23C6 (Cr rich) decorating the grain boundaries.

Effects of Temperature on the Microstructure

The most obvious effects of high temperature on the matrix gamma prime precipitate are changes in:

Concentration

Size

Distribution

Other microstructural changes are:

Coalescence of the phases and gamma-prime eutectic

Decomposition and solutioning of carbides

Stability of matrix (that is, incipient melting).

The effects of temperature in the range 2000 to 2300 deg F (1094 to 1260 deg C) on the microstructure of this alloy are shown in Figure thru Figure. They are microstructures representative of temperature and stress on IAE 1422 nickel-based alloy.

Figure thru Figure are views of a leading edge section of a first stage turbine blade run in a V2500 experimental engine; therefore, they are microstructures representative of temperature and stress on IAE 1422 nickel based blades.

Fig. 70-02-10-990-006 thru Figure represent microstructures for static furnace temperature attainments to 2200 deg F (1204 deg C), 2250 deg F (1232 deg C), and 2300 deg F (1260 deg C).

Description of Micrographs Illustrating Microstructural Features

NOTE

The microstructure specimens should be examined with 1000X optical microscope equipment.

Figure shows fully heat treated IAE 1422 with a duplex array of fine gamma prime precipitate (Circles A), coarse gamma prime precipitate (Circles B), gamma-gamma prime eutectic islands (Arrows C), and MC-type carbides (Arrows D).

NOTE

A metal temperature of 2000 deg F (1094 deg C) causes some solutioning of the fine matrix gamma prime precipitate and slight agglomeration of the coarse matrix gamma prime precipitate.

Figure shows the slight solutioning of the fine matrix precipitate (Circles A), and slight agglomeration of coarser matrix precipitate (Circles B).

NOTE

A metal temperature of 2050 deg F (1121 deg C) causes more solutioning and agglomeration of the fine matrix gamma prime precipitate and agglomeration of coarser matrix precipitate. The agglomerated fine precipitate more closely resembles the coarser precipitate bordering the islands of eutectic gamma prime. Significant agglomeration of the coarse precipitate is evident.

Figure shows the partial solutioning and agglomeration of fine matrix precipitate (Circles A), and agglomeration of coarser matrix precipitate (Circles B).

NOTE

A metal temperature of 2100 deg F (1149 deg C) causes the solutioning of the fine precipitate to be at a more advanced stage, and some solutioning of the coarser precipitate, with a decrease in the density of both precipitates.

Figure shows moderate solutioning of fine matrix precipitate (Circles A), and slight solutioning of coarse precipitate (Circles B).

NOTE

A metal temperature of 2150 deg F (1177 deg C) causes extensive solutioning of the fine precipitate with a marked decrease in precipitate population. If any of the initial fine gamma prime precipitate is remaining in the microstructure, the maximum metal temperature has not exceeded 2150 deg F (1177 deg C). Moderate solutioning of coarse matrix precipitate also occurs and some decomposition of carbides and slight coalescence of eutectic gamma prime is also evident.

Figure shows areas of extensive solutioning of fine matrix precipitate (Circles A), moderate solutioning of coarse precipitate (Circles B), and coalescence of eutectic islands (Arrows C).

NOTE

A metal temperature of 2200 deg F (1204 deg C) causes complete solutioning of the fine gamma prime precipitate and extensive solutioning of coarse gamma prime precipitate. More advanced coalescence of eutectic gamma prime is also evident.

Figure shows complete solutioning of fine matrix precipitate (Circles A), and extensive solutioning of coarse matrix precipitate (Circles B).

NOTE

A metal temperature of 2250 deg F (1323 deg C) causes the solutioning of the fine and coarse matrix gamma prime precipitates to be completed. Coalescence and partial solutioning of eutectic gamma prime and incipient melting of matrix around MC carbides and eutectic gamma prime islands are also evident.

Figure shows complete solutioning of fine and coarse matrix gamma-gamma prime precipitate (Circles A), and incipient melting (Arrows E).

NOTE

A metal temperature of 2300 deg F (1260 deg C) causes extensive melting in the grain boundaries, interdendritic areas, and around carbides. See Figure.

Figure shows complete solutioning of matrix precipitate (Circles A), and extensive melting in grain boundaries (Arrows E).

Preliminary Requirements

Pre-Conditions

NONE

Support Equipment

NameManufacturerPart Number / IdentificationQuantityRemark
Optical microscopic equipmentLOCALOptical microscopic equipment

1000x

Consumables, Materials and Expendables

NONE

Spares

NONE

Safety Requirements

NONE

Procedure

    2. Figure: Fig 70-02-10-990-001

    Fig 70-02-10-990-001

    Figure:

    Figure:

    Figure:

    Figure:

    Figure:

    Figure:

    Figure:

Requirements After Job Completion

Follow-On Conditions

NONE
Manufacturer Code:LOCAL
Enterprise Name:LOCALLY SUPPLIED
Manufacturer Code:LOCAL
Tool Number:Optical microscopic equipment
Tool Name:Optical microscopic equipment