Office of Research, UC Riverside
Suveen Mathaudhu
Associate Professor
Mechanical Engineering
suveen@ucr.edu
(951) 827-4414


Collaborative Research: Fundamental Investigation of Fatigue Crack Growth Mechanisms in Microstructurally-Stable Nanocrystalline Alloys

AWARD NUMBER
008836-002
FUND NUMBER
33328
STATUS
Active
AWARD TYPE
3-Grant
AWARD EXECUTION DATE
4/14/2017
BEGIN DATE
4/15/2017
END DATE
3/31/2020
AWARD AMOUNT
$245,143

Sponsor Information

SPONSOR AWARD NUMBER
1663522
SPONSOR
NATIONAL SCIENCE FOUNDATION
SPONSOR TYPE
Federal
FUNCTION
Organized Research
PROGRAM NAME

Proposal Information

PROPOSAL NUMBER
17030310
PROPOSAL TYPE
New
ACTIVITY TYPE
Basic Research

PI Information

PI
Mathaudhu, Suveen
PI TITLE
Other
PI DEPTARTMENT
Mechanical Engineering
PI COLLEGE/SCHOOL
Bourns College of Engineering
CO PIs

Project Information

ABSTRACT

Metallic materials with a crystallite size of sizes less than 100 nanometers (known as nanocrystalline alloys) have enhanced strength and toughness compared to those with much larger crystal sizes. These crystals tend to grow rapidly, however, when exposed to cyclic external forces, limiting their practical utility as load-bearing structures. This award supports fundamental research to enable enhanced stability in nanocrystalline alloys and to uncover their behavior under cyclic loading conditions, by applying innovative alloy design and synthesis methods. Further, this project will develop a predictive framework which will identify suitable compositions of novel nanocrystalline alloys that will meet or exceed the performance of conventional alloys under cyclic loads, including rotating machinery and engine components critical to the transportation, defense and energy sectors. This interdisciplinary research will provide opportunities for students from underrepresented minority groups, women, and persons with disabilities, and will directly raise public interest in science and engineering through creative outreach initiatives.

Metals with a mean grain size below 100 nm have inspired much research interest owing to their superior mechanical properties as compared to course-grained materials. However, despite the potential applicability of nanocrystalline alloys for load-bearing structures, very few studies have addressed the fundamental microstructural evolution under fatigue loads, specifically, grain size effects on fatigue processes. The critical gap in knowledge has stemmed from microstructural instability, i.e., grain growth and texture evolution observed during cyclic deformation. Motivated by this, the goals of this project are: (1) implementation of selective segregation of nanoclusters to lower the thermodynamic and kinetic driving forces for grain growth, and as a result, a clear understanding of the true microstructural grain size effects on salient fatigue growth mechanisms can be unraveled; and (2) to exploit the subsequent knowledge to reconcile key theories and hypotheses pertaining to fatigue crack growth behavior of nanocrystalline metals. The fatigue crack growth mechanisms as a function of grain size quantified in this project have broad scientific ramifications as this knowledge is highly relevant for designing and synthesizing nanocrystalline alloys with optimal microstructures, and for accurate predictive simulations.
(Abstract from NSF)