Nanoindentation Study on the Creep Characteristics and Hardness of Ion-Irradiated Alloys

Zhu, Zhenbo; Huang, Huijie; Liu, Jizhao; Ye, Linfeng; Zhang, Zhu

doi:10.3390/ma13143132

Cited by 12 publications

(1 citation statement)

References 40 publications

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“…Hardness testing is widely used to evaluate the plastic deformability of materials. In the last few decades, nanoindentation testing methods [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ] have been developed and are rapidly becoming widespread for the evaluation of various materials, including steels [ 19 ], tungsten [ 20 ], copper [ 21 ], and NiTi alloys [ 22 ]. This has produced new metallurgical knowledge about nanoscale deformation that is useful for the development of superior materials.…”

Section: Introductionmentioning

confidence: 99%

Hardness–Deformation Energy Relationship in Metals and Alloys: A Comparative Evaluation Based on Nanoindentation Testing and Thermodynamic Consideration

2021

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Nanoindentation testing using a Berkovich indenter was conducted to explore the relationships among indentation hardness (H), elastic work energy (We), plastic work energy (Wp), and total energy (Wt = We + Wp) for deformation among a wide range of pure metal and alloy samples with different hardness, including iron, steel, austenitic stainless steel (H ≈ 2600–9000 MPa), high purity copper, single-crystal tungsten, and 55Ni–45Ti (mass%) alloy. Similar to previous studies, We/Wt and Wp/Wt showed positive and negative linear relationships with elastic strain resistance (H/Er), respectively, where Er is the reduced Young’s modulus obtained by using the nanoindentation. It is typically considered that Wp has no relationship with We; however, we found that Wp/We correlated well with H/Er for all the studied materials. With increasing H/Er, the curve converged toward Wp/We = 1, because the Gibbs free energy should not become negative when indents remain after the indentation. Moreover, H/Er must be less than or equal to 0.08. Thermodynamic analyses emphasized the physical meaning of hardness obtained by nanoindentation; that is, when Er is identical, harder materials show smaller values of Wp/We than those of softer ones during nanoindentation under the same applied load. This fundamental knowledge will be useful for identifying and developing metallic materials with an adequate balance of elastic and plastic energies depending on the application (such as construction or medical equipment).

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