Mesoscale Mechanical Behaviors and Damage Mechanisms of Authentic Lunar Breccia under Wide Temperature Conditions

Description

The document contains all the relevant data (including elastic modulus, hardness, fracture toughness, and energy) for the four regions of the nanoindentation at temperatures ranging from 120°C to -120°C.

Steps to reproduce

Nanoindentation tests were performed using a Bruker Hysitron TI 980 nanoindenter equipped with a Berkovich triangular diamond indenter. A loading-holding-unloading protocol was adopted at each target temperature: the load was increased from zero to a peak of 150 μN at a constant rate of 15 μN/s, held at the peak load for 20 s to minimize thermal drift and time-dependent deformation effects, and then unloaded to zero at the same rate of 15 μN/s. A 5 × 6 matrix indentation pattern was applied in the intact zones of olivine and plagioclase, while single-point sequential indentation tests were conducted along the extension directions of mineral interfaces and olivine fracture boundaries. Target temperatures ranged from 120 °C to −120 °C (specifically 120, 25, −40, −60, −80, −100, and −120 °C), with heating and cooling rates below 10 °C/min. After reaching each target temperature, the sample, indenter, and test chamber were maintained isothermally for 30 min to ensure thermal equilibrium prior to testing. From the resulting load-displacement curves, the elastic modulus and hardness were determined using the Oliver–Pharr method. The total input energy, elastic energy, plastic energy, and fracture energy were derived by integrating the loading and unloading curves. The mesoscopic fracture toughness K~IC~ was then calculated from the fracture energy based on the energy-based indentation fracture toughness method.

Institutions

• Shenzhen University

  Guangdong, Shenzhen

Categories

Licence