Interpreting test temperature and loading rate effects on the fracture toughness of polymer-metal interfaces via time–temperature superposition

Journal Article · Sat May 04 00:00:00 EDT 2024 · International Journal of Fracture

DOI:https://doi.org/10.1007/s10704-024-00790-7· OSTI ID:2566719

DelRio, Frank W. ^[1]; Huber, Todd ^[1]; Jaramillo, Rex K. ^[1]; Reedy Jr., E. David ^[1]; Grutzik, Scott J. ^[1]

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1. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

Here, in this letter, we present interfacial fracture toughness data for a polymer-metal interface where tests were conducted at various test temperatures T and loading rates $$\dot{δ}$$. An adhesively bonded asymmetric double cantilever beam (ADCB) specimen was utilized to measure toughness. ADCB specimens were created by bonding a thinner, upper adherend to a thicker, lower adherend (both 6061 T6 aluminum) using a thin layer of epoxy adhesive, such that the crack propagated along the interface between the thinner adherend and the epoxy layer. The specimens were tested at T from 25 to 65 °C and $$\dot{δ}$$ from 0.002 to 0.2 mm/s. The measured interfacial toughness Γ increased as both T and $$\dot{δ}$$ increased. For an ADCB specimen loaded at a constant $$\dot{δ}$$, the energy release rate G increases as the crack length a increases. For this reason, we defined rate effects in terms of the rate of change in the energy release rate $$\dot{G}$$. Although not rigorously correct, a formal application of time–temperature superposition (TTS) analysis to the Γ data provided useful insights on the observed dependencies. In the TTS-shifted data, Γ decreased and then increased for monotonically increasing $$\dot{G}$$. Thus, the TTS analysis suggests that there is a minimum value of Γ. This minimum value could be used to define a lower bound in Γ when designing critical engineering applications that are subjected to T and $$\dot{δ}$$ excursions.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: NA0003525
• OSTI ID: 2566719
• Report Number(s): SAND--2025-06001J
• Journal Information: International Journal of Fracture, Journal Name: International Journal of Fracture Journal Issue: 3 Vol. 247; ISSN 0376-9429
• Publisher: Springer
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Fracture toughness
asymmetric double cantilever beam
polymer-metal interfaces
small-scale yielding
time-temperature superposition