Microsystems for Harsh

Environments

METALS

Our goal is to develop and demonstrate a MEMS-based 

methodology for evaluating time dependent mechanical 

properties and reliability of materials that undergo exposure 

to extreme and harsh environments (e.g., temperature, 

radiation, corrosive chemistries, etc.). As a first application, 

we are developing this method to evaluate the effects of 

long term, high flux radiation exposure on materials used 

in nuclear power plant construction. Our MEMS-based 

test platforms will be used to validate the continued use 

of current facilities and accelerate development of next 

generation nuclear plants (NGNP).

Objective

Impact and Customers

• Currently, the country’s 100 operating nuclear power plants supply more than 20 % of our electricity, accounting for over 

70 % of our carbon dioxide free electricity production.

• Nuclear power plants emit virtually no carbon dioxide during operation. 

Even considering “full life cycle emissions,” including the mining and 

transportation of fuel, plant construction, and waste considerations, 

nuclear carbon dioxide discharges are comparable to wind and 

hydropower, and less than solar power.

• The average U.S. nuclear power plant has been in operation for over 

24 years, already half of the original operational license period. 

• To maintain our current capacity through lifetime extension, or to 

increase capacity through NGNP, a rapid assessment of materials 

properties under long term irradiation exposure is necessary. 

• Small specimen test technology will accelerate materials development 

and evaluation through the simultaneous testing of large arrays of 

microspecimens, systematically varied in composition and/or heat 

treatments, including time dependent effects.

Approach

Materials Science and Engineering Laboratory

Classically, material property evaluation is performed with macroscopic 

specimens and test methods. In contrast, we are developing new MEMS-based 

test methods to evaluate the properties of bulk materials in environments where 

macroscopic methods are not applicable, extremely difficult, or exceptionally 

costly. The properties of the small scale structures will be linked to those 

of bulk scale structures through comparative testing, coupled with imagebased finite element models. Currently, we are developing techniques using 

focused ion beam (FIB) milling to section microsized specimens from structural 

materials previously irradiated in test reactors, accelerators, or working power 

reactors, for insertion into prefabricated on-chip load frames. Ultimately, we 

plan to fabricate an array of test structures with on-chip control, actuation, 

and sensing, allowing for long term, in situ, harsh environment testing in high 

irradiation environments.

853-05-05a
Materials Science and Engineering Laboratory

This project was initiated in FY09 and combines 

expertise within the Materials Reliability Division 

in the areas of macroscale and microscale 

property evaluation.

Microscale Property Evaluation

Accessing the as-fabricated properties of 

materials used in integrated circuits and other 

related devices is critical to their continued 

scaling. For the past two decades, the Materials 

Reliability Division has been developing 

new methods to test materials reliability at 

increasingly small dimensions. Initially, we 

focused on the development of a microscale 

tensile test system to measure elastic and plastic 

properties of free standing, patterned thin 

films. As device complexity increased, however, 

new methods were needed to address buried 

layers and interconnects. Because interconnect 

properties are determined by both the material 

and the influence of the immediate interconnect 

environment (which could not be measured 

directly with the microtensile test), we developed 

an electrically based method to measure the 

properties of as-fabricated structures. Through 

the use of high density current cycling, we have 

evaluated properties such as ultimate tensile 

strength and cyclic lifetime of these materials.

Fabricated On-Chip Test Methods

In addition to measuring the properties of 

advanced electronic materials, we also have 

expertise in the measurement of materials such 

as living cells. We recently demonstrated a 

unique bio-MEMS device that stretches a single 

live adherent cell and measures its corresponding 

mechanical response. Due to the small size of 

living cells, this unique approach relied on the 

use of microfabrication techniques to prepare 

a protein-coated miniaturized load frame, onto 

which a cell could be grown, observed through 

a transparent window, and measured using 

calibrated on-chip load spring and displacement 

sensors. This technique provided a proof of 

principle demonstration of our ability to design 

and fabricate on-chip materials measurement 

devices.

Reliability of Structural Materials

In addition to small scale mechanics, the 

Division has a 50+ year history in measuring 

fracture and deformation in large scale 

structural materials. Most recently, we have 

been applying this expertise to pipeline steels, 

and adapting the Crack Tip Opening Angle 

(CTOA) method for characterizing fully plastic 

fracture. Our research focuses on improving 

the optical imaging technique for determining 

the crack tip opening angle, standardizing the 

measurement method to reduce uncertainty in 

the data. This method has been successfully 

employed to measure the effects of aging and 

operational conditions on the fatigue crack 

growth rates of steels, spanning five different 

strengths and more than 70 years of operation.

Evaluation of Materials Properties for Operation 

in Harsh Environments

Our research into pipeline safety does not end 

with aging effects. On the forefront of pipeline 

research is the issue of materials compatibility 

for distribution of alternative fuels. For example, 

the future “hydrogen economy” will depend on 

efficient transport of hydrogen, likely using the 

existing network of oil and gas pipelines; thus, 

hydrogen degradation of the pipelines is likely 

to occur, and quantifying it will be critical.

We conducted tests to evaluate the effects of 

hydrogen on the fatigue life of pipeline steels. 

Specimens were prepared with and without 

surface tinning, and then electrochemically 

hydrogen charged to determine the effects of 

surface preparation on hydrogen dissolution. Our 

results show a two-order-of-magnitude increase 

in fatigue rate when specimens were hydrogen 

charged. Data on hydrogen effects is limited, 

indicative of the challenges associated with 

performing such tests, and illustrating the need for 

alternative approaches to fully evaluate materialenvironment interactions under harsh conditions.

Accomplishments

Sudook Kim

Nick Barbosa

(Materials Reliability Division)

(303) 497-3445

barbosa@nist.gov 

www.nist.gov/reliability

Learn More Publications

Barbosa III N, Keller RR, Read DT, Geiss RH and Vinci RP Comparison of Electrical and 

Microtensile Evaluation of Mechanical Properties of an Aluminum Film Metallurgical and 

Materials Transactions, 38A: 2160 (2007)

Serrell DB, Oreskovic TL, Slifka AJ, Mahajan RL and Finch DS A Uniaxial BioMEMS 

Device for Quantitative Force-displacement Measurements Biomed. Microdev., 9 (2): 

267 (2007)

Darcis PhP, McCowan CN, Windhoff H, McColskey JD and Siewert TA Crack Tip 

Opening Angle Optical Measurement Methods in Five Pipeline Steels Engr. Fracture 

Mech., 75: 2453 (2008)

Siewert TA, McColskey JD and Ricker RE Report of NIST Workshop on Materials Test 

Procedures for Hydrogen Pipelines NISTIR, 6649 (2007)

Bio-MEMS, single cell test device

High speed CTOA Load Frame

Effect of hydrogen on fatigue rate

UTS estimation for Al interconnects