Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Archives of Metallurgy and Materials

2 2021

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

The Effects of Grain Boundary Structures on Mechanical Properties in Nanocrystalline Al Alloy

Jang Jin Man, Lee Wonsik, Ko Se-Hyun

Archives of Metallurgy and Materials

2021

Vol. 66, iss. 4

971--975

This study investigates the effects of grain boundary structures on mechanical properties of nanocrystalline Al-0.7Mg-1.0Cu alloy using nanoindentation system. Grain boundary structure transforms to high angle grain boundaries from low angle ones with increase of heat treatment temperature and the transformation temperature is about 400°C. Young’s modulus and hardness are higher in sample with low angle grain boundaries, while creep length is larger in sample with high angle ones. These results indicate that progress of plastic deformation at room temperature is more difficult in sample with low angle ones. During compression test at 200°C, strain softening occurs in all samples. However, yield strength in sample with low angle grain boundaries is higher twice than that with high angle ones due to higher activation energy for grain boundary sliding.

Effects of SiC Coating of Carbon Fiber on Mechanical Properties in Short Carbon Fiber Reinforced Al Matrix Composite

Jang Jin Man, Ko Se-Hyun, Lee Wonsik

Archives of Metallurgy and Materials

2021

Vol. 66, iss. 4

941--946

A356 Al composites reinforced by short carbon fiber were prepared through the 2-step process: fabrication of a composite precursor and ultrasonication of the precursor melt. The short carbon fibers were coated with 0.15~1.5 μm thick SiC layer by a car-bothermal reaction, and an amount of the carbon fiber reinforcement was determined to be 1.5 vol.% and 4.0 vol.%, respectively. The addition of the carbon fiber increased the hardness of A356 alloy. However, tensile strength did not increase in the as-cast composites regardless of the SiC coating and volume fraction of the carbon fiber, due to the debonding which reduced load transfer efficiency from matrix to fiber at the interface. After T6-treatment of the composites, a significant increase in strength occurred only in the composite reinforced by the SiC-coated short carbon fiber, which was considered to result from the formation of a precipitate improving the Al/SiC interfacial strength.