The Effect Of Grain Size On The Mechanical Properties Of Aluminum

Abstract

Although many studies have focused on the unique plastic deformation behavior of nanocrystalline aluminum (e.g., the positive deviation from Hall-Petch relation, the unusual yield-drop phenomenon in tensile mode, etc.), the data reported by different research groups are inconsistent with each other, possibly because of different fabrication processes. In this study, aluminum samples with a wide grain-size spectrum -from a few micrometers down to 100 nanometers -are manufactured by powder metallurgy. The grain size was measured by X-ray diffraction analysis and transmission electron microscope observation. Furthermore, the tensile behavior, which varied according to a grain size, is discussed with a comparison of the theoretical models.

Tensile nanomechanics and the Hall-Petch effect in nanocrystalline aluminium

“…4(a) [9][10][11]. Two distinct regions of normal and inverse HP relationships (shown as black dashed lines) are observed, from which a threshold value of about 30 nm is identified.…”

“…As a consequence, a maximum threshold value of yield stress or hardness is generally reached at certain grain size level for a given nanocrystalline metal or alloy. Numerous reports show that the transition of positive to negative slope in the HP relationship is around 10-40 nm for varied nanocrystalline metals and alloys [6][7][8], such as Al [9][10][11], Fe [12], Cu [6,13,14], Cu-Ta [15], Ni [6], Ni-P [13], Zr [16], and Zn [17] among others.…”

Achieving strong and stable nanocrystalline Al alloys through compositional design

“…Mohamed used the model of dislocation-accommodated boundary sliding and associated the critical size to the sliding rate, the activation energy and volume and decided the critical grain size for Al to be ~ 110 nm [86]. Empirical evidences reflected a critical size of ~ 40 nm at the crossover of deformation mechanism transition for Al [87].…”

ANALISA PERMUKAAN MATERIAL ALUMINIUM PADUAN (AlSiCu) HASIL NITRIDASI ION

“…Menurut hukum Hall Petch bahwa kekuatan bahan itu berbanding terbalik dengan ukuran butir [13,14]. Dengan makin besarnya ukuran butir maka kekuatannya menurun.…”