Bonding Test를 실시하여 Sn-Pb Solder와 Pb-Free Solder 간의 차이를 확인하고 Pb-Free Solder중에서도 각 재료마다의 Mechanical Bonding Test를 실시하여 Bonding Force를 체크한다. 보통 Soldering 된 제품이 받는 Stress 는 Tensile Stress 보다는 Shear Stress 가 주요하기 때문에 Solder 선택 시에는 Solder의 Tensile Property 보다는 Shear Pr
In describing the answer to the question below, try to share your opinions on the basis of evidences such as articles and books. Also provide information of the evidence (author, title, journal name, etc.).
1. Explain what happens in terms of mechanical/chemical properties when making products using metal-based 3D additive manufacturing technology. (10 points)mechanical properties
전통적
What is Amorphous metal?
Polycrystalline grains of varying shapes and sizes
Misaligned planes of atoms slip past each other easily, absorbing energy and allowing dislocations to move, making deformation permanent.
Grain boundaries represent weak spots
Also called Metallic glasses or glassy metals
Cooled faster than atoms can rearrange into a crystal.
Dislocation movement obstructed s
1 GPa
Elastic modulus Nanoindentation > 6 GPa
Adhesion Tape pull, modified-edge lift-off Delamination-free
Disavantages
Weakens mechanical properties
Lower thermal conductivity
Narrow pore distribution to ensure dielectric constant is homogeneous and isotropic
Pores need to be closed cells to prevent crack propagation and moisture absorption
Need to add silica to seal surface pores
temperature, respectively. The electrical properties of the films were determined using Hall measurement system (Van der Pauwconfiguration, Hilton, Australia) at room temperature. Optical absorption studies were carried out by using UV-Vis spectrometer (Cary 100, Varian, Mulgrave, Australia) at room temperature. Photoluminescence (PL) spectra were obtained using a closed-cycle liquidhelium cry ge