1. Motivation 4.

Test Matrix
• To increase the efficiency and longevity of
An Accelerated Creep Testing (ACT) Program for Test 2 – Test-parameter decision matrix for SIM and SSM

Advanced Creep Resistant Alloys for High

SIM Maximize Acceleration?
fossil energy (FE) power plants, advanced 0  0 set to the design stress.
ultrasupercritical (A-USC) power plants are
Temperature Fossil Energy (FE) Applications
T0 T0 set to the design temperature.
being implemented; T0  
T  TT  T0 3 where TT is the temperature of the next mechanism transition.
Amanda C. Haynes, Dulce Zamorano, Robert Mach, Jack F. Chessa, Calvin M. Stewart
• The A-USC power plants operate for over t t  0 minimizes real time thus maximizes the acceleration.
Department of Mechanical, University of Texas El Paso, Texas, Tx 79902
10,000 hours at pressures above 4000 psi and SSM Maximize Acceleration?
2. Systematic Approach to SIM and SSM 0  0 set to the design stress.
temperatures above 1400°F;
• The materials used in these power plants The Research Objective (RO) of this project is to vet, improve, and test the feasibility of the SIM and SSM T 0 T  
 0 T    T 3 where  is the stress of the next mechanism transition.

require qualification to withstand these accelerated creep tests for metallic materials. T0 T0 set to the design temperature.
t t  0 minimizes real time thus maximizes the acceleration.
conditions using accelerated creep testing Initial Horizontal and Vertical Adjustments 0.030
(ACT).   MPa 600°C
  cr  cr

Creep Strain , cr (mm/mm)

cr  cr     elastic   thermal   comp   slip 0.025
10
9 600°C 300 MPa

Creep Strain

Creep Strain
8 320 MPa

(%)
 2 ,T2

Creep Strain
Can we capture this uncertainty in an accelerated * 7

cr
t 0.020 6

 2 ,T2

Creep Strain,
 2 ,T2
5

r 4

Stress
Strain
3

manner?  1 ,T1
2
1

 2 ,T2  1 ,T1  1 ,T1

0.015 0
0 20 40 60 80 100
Time, t (hr)
120 140 160

 1 ,T1  0 ,T0  0 ,T0  0 ,T0

 0 ,T0
0.010
Uncertainty ↑ 0 0 0
CCT Reference
SSM MPa
0.005
Temperature ↑ t  c t Time t t0 Time t0 t Virtual Time t  t0
(a) Time (b) (c) (d)
Stress ↓ 0.000
0 20 40 60 80 100 120 140 160 180
Reference-Calibration of SSM Self-Calibration of SSM Accelerated Creep Curve
Time, t (hours)

 cr log i   f  0 , T0 ,  i , Ti  , ti* 

ti  t0
 cr  0  cr 0 304 SS Preliminary ACT Test
i 2
2 5. Acceleration Software

Creep Strain
2

Creep Strain
Creep Strain

1 1 1 SSM Acceleration Software

 E ,i   S ,i 1
Experimental Data File
0 0
0 CCT Reference 0  E ,i   S ,i 1
0
300,000 hours Global Inputs
Creep-Rupture of 9Cr-1Mo Tube
(e) Time t (f) Log10 Time log  t  (g) Accelerated Time t
# of Stress Steps

Initial Stress
(a) Total Strain-Time Data, (b) Creep Strain Adjustment, (c) Extrapolation to Zero Strain, (d) Virtual Start Time Adjustment, (e) Reference
Stress Increment
– Calibration, (f) Self – Calibration, (g) Accelerated Creep Curve
Table 1 - Material qualification procedure using Accelerated Creep
Temperature
Testing (ACT)
Procedure Advantages
3. Test Setup MERG HT DIC System Run Save Exit
Disadvantage
Conventional Creep • Traditional • Destructive Mock User Interface for the ACT Software
Test (CCT) • Full Creep • Large Strains
Creep measurements Deformation • Long Times Subroutine 2:
•
Subroutine 1:
occur at constant Curve Fracture Calibrate McVetty’s
Quartz View Port

stress (in practice • Rupture Life Processes Data Processing

Law for each step
constant load) with • Simple • Major State
standard or small Equipment Changes Gas Port

punch specimen Subroutine 3:

Stepped IsoStress • Short Times • Destructive 50kN · 1200 C Calibrate Time Factors
Method (SSM) and • Full Creep • Large Strains
Equipment for SSM
Stepped Deformation • Fracture Subroutine 4:
IsoThermal Method Curve Processes Instron 5969 (50kN capacity) High Temperature DIC with Ultraviolet (UV) Subroutine 5:
(SIM) • Rupture Curve • Major State ATS Series 3120 Split Tube Furnace Ambient up to 1200 C with Watlow PM Light Data Acceleration and
Output Results and
Creep measurements Changes Epsilon Model 3549 Mountable High Temperature Extensometer Generate Deformation
Error Analysis
occur at constant • Sensitive to Reference Stress Reference Temperature Furnace Curve
T0  c 3
0  c  cr
stress that is stepped Regression
 cr
T3 Matlab Code Flow Chart
increased after a Analysis T2 2
• Advanced 450nm
fixed interval T1 1
Spotlight
 cr
Equipment
0
Creep Strain

• •
Creep Strain

Stress Relaxation Multiple Sensitive to Data T0

Camera
Approach (SRT) Isotherms of Resolution
(c)

Creep Strain
Relaxation Data • Sensitive to
450nm
measurements occur • Creep Activation Numerical
Bandpass  2 ,T2 (d)
at constant strain Energy Integration Time
(sometimes constant • Non-Destructive Scheme
(a) Time
t (b) t filter (b)  1 ,T1
Unified Master Curve
displacement) near • Small Strain • Does Not SSM or SIM
0  c
the elastic limit • Short Times Provide  cr  cr 0  c
Unfiltered 450 nm
(a)
CCT
• No Fracture Full Creep T0  c T0  c
Room Temp

Room Temp
Processes Deformation Time t
• Nearly Constant Curves
log i   f  0 , T0 ,  i , Ti 
Creep Strain

Time-Temperature-Stress Superposition
Creep Strain

State • Does Not

Provide
Rupture
A. Acknowledgement
•
C.
Advanced Department of Energy
Equipment (c) Accelerated Time log  t / i  (d) Time
t National Energy Technology Laboratory
Conventional Creep Tests (CCTs) Award number: DE-FE0030331