Microstructure, mechanical properties and strengthening mechanisms of IN738LC alloy produced by Electron Beam Selective Melting

The effect of lanthanum (La)+cerium (Ce) addition on the high-temperature strength of an aluminum (Al)–silicon (Si)–copper (Cu)–magnesium (Mg)–iron (Fe)–manganese (Mn) alloy was investigated. A great number of plate-like intermetallics, Al11(Ce, La)3- and blocky α-Al15(Fe, Mn)3Si2-precipitates, were observed. The results showed that the high-temperature mechanical properties depended strongly on the amount and morphology of the intermetallic phases formed. The precipitated tiny Al11(Ce, La)3 and α-Al15(Fe, Mn)3Si2 both contributed to the high-temperature mechanical properties, especially at 300 °C and 400 °C. The formation of coarse plate-like Al11(Ce, La)3, at the highest (Ce-La) additions, reduced the mechanical properties at (≤300) ℃ and improved the properties at 400 ℃. Analysis of the strengthening mechanisms revealed that the load-bearing mechanism was the main contributing mechanism with no contribution from thermal-expansion mismatch effects. Strain hardening had a minor contribution to the tensile strength at high-temperature.

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The Structure and Mechanical Properties of Hemp Fibers-Reinforced Poly(ε-Caprolactone) Composites Modified by Electron Beam Irradiation

Applied Sciences ◽

10.3390/app11125317 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5317

Author(s):

Rafał Malinowski ◽

Aneta Raszkowska-Kaczor ◽

Krzysztof Moraczewski ◽

Wojciech Głuszewski ◽

Volodymyr Krasinskyi ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Electron Beam ◽

Impact Strength ◽

Flexural Modulus ◽

Natural Fibers ◽

High Energy ◽

Electron Radiation ◽

Elongation At Break ◽

Hemp Fibers

The need for the development of new biodegradable materials and modification of the properties the current ones possess has essentially increased in recent years. The aim of this study was the comparison of changes occurring in poly(ε-caprolactone) (PCL) due to its modification by high-energy electron beam derived from a linear electron accelerator, as well as the addition of natural fibers in the form of cut hemp fibers. Changes to the fibers structure in the obtained composites and the geometrical surface structure of sample fractures with the use of scanning electron microscopy were investigated. Moreover, the mechanical properties were examined, including tensile strength, elongation at break, flexural modulus and impact strength of the modified PCL. It was found that PCL, modified with hemp fibers and/or electron radiation, exhibited enhanced flexural modulus but the elongation at break and impact strength decreased. Depending on the electron radiation dose and the hemp fibers content, tensile strength decreased or increased. It was also found that hemp fibers caused greater changes to the mechanical properties of PCL than electron radiation. The prepared composites exhibited uniform distribution of the dispersed phase in the polymer matrix and adequate adhesion at the interface between the two components.

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