Magnesium alloy is becoming known for the lightest material in the metallic materials. Recently the automotive industry has a variety application to the light weight parts replacement. This study focuses on the mechanical property improving through a tiny amount’s CNT addition into the magnesium alloy as AM60. The CNT material is an arduous combination of the metallic materials. Therefore this study is concentrating on the contact force growth for the CNT material. Consequently, the made CNT is produced by the CVD process using the magnesium catalyst. The CNT material has dispersive with mechanical process into the molten AM60 alloy. The mechanical experiment result that hardness is 18% increasing and tensile strength is 13% increasing, better than the raw AM60 alloy on this investigation.

The characteristics of CNT-Polyamide composites were analyzed, that is, tensile strength, electrical resistivity, and thermal conductivity were measured according to the align length of CNT. There have been researches on the influence of aligned CNT to improve the mechanical and thermal characteristics in different areas including absorption and shielding of electromagnetic wave, thermal distribution or absorption, and high-strength of CNT. The aligned CNTs were synthesized by the ethylene gas with a CVD device preheated at 650℃. CNT-Polyamide composites were produced with the mixing of solution. CNT contents were controlled from 1phr to 50phr in the polyamide-ethanol solution, and blended with the 700W bar-type ultrasonic wave for 60 min.. And then CNT-polyamide were precipitated by CNT-polyamide-etnanol falling into the cold water. After dried 12 hours, CNT-polyamide composite were pressed at 150℃~180℃ with 400kgf to get the thickness of 1mm. As the conclusions, aligned CNT bundles were dispersed by cutting of CNT to the aligned direction because of polyamide properties. Tensile strength and electrical resistivity were improved to the increase of aligned length of CNT. Thermal conductivity was little affected by the align length of CNT.

The effect of CNT diameters on properties of CNT-polyamide composites was investigated such as electrical conductivity, tensile strength and thermal conductivity. To get different diameter distributions of CNTs, several portions of Mo and Fe in Mo-Fe/MgO catalysts were synthesized by a combustion method at 600℃. And all CNTs growed at 900℃ with 3 SLM methane and 1 SLM hydrogen for 40min. Four kinds of CNTs with different diameter distributions, such as 1~3nm, 3~7nm, 7~13nm, and 10~30nm, were selected to make CNT-polyamide composites. Each composite was manufactured by a solution mixing using bar-type ultra-sonicator in the CNT portions from 1phr to 50phr. And electrical conductivity, tensile strength, and thermal conductivity were measured. Three properties of CNT-polyamide composite, manufactured with 10nm diameter, were more excellent compared to other composites, with electrical conductivity  Ω at 7phr, thermal conductivity 2.4.W/mK at 40phr, tensile strength 60MPa at 30phr. CNTs with a diameter of 10nm were superior to other diameters for the multi-functional composite such as CNT-polyamide composites.

Recently, the need of weight reduction has been required in automobile industry. In this paper, we aim to evaluate the composite sandwich panel to substitute original steel structure of commercial vehicle. The compressive and drum-peel tests were conducted to consider core materials and resin system of the sandwich panel. Based on the test, we decided the core reinforcement and matrix materials of the panel. As a result, the composite panel were composed of aluminum profile, glass fiber prepreg and aluminum honeycomb. We also confirmed the weight reduction ratio and structural safety compared to prior steel structure components by bending test and FEM simulation.