# $Al/{Al_2}{O_3}$금속복합재료의 기계적 성질과 피로거동

• Song, Jeong-Il (Dept. of Mechanical Engineering, Pohang University of Science and Technology) ;
• LIm, Hong-Jun (LG Electronics) ;
• Han, Gyeong-Seop (Dept. of Mechanical Engineering, Pohang University of Science and Technology)
• 송정일 (포항공과대학교 기계공학과) ;
• 임홍준 (LG전자(주) 생활시스템연구소) ;
• 한경섭 (포항공과대학교 기계공학과)
• Published : 1996.03.01
• 25 5

#### Abstract

The metal matrix composites(MMC) are currently receiving a great deal of attention. These composites possess exellent mechanical and physical properties such as modulus, strength, wear resistance and thermal stability, which make them very attractive for use in automotive piston. In this study, $Al/{Al_2}{O_3}$(15%) composites are fabricated by the squeeze casting method. Mechanical properties such as tensile strength and ductility are performed at room and elevated temperature($250^{\circ}C$ and $350^{\circ}C$), respectively. Through thermomechanical analyser, thermal expansion coefficient of $Al/{Al_2}{O_3}$ composites are conducted for ranging from room temperature to ($400^{\circ}C$.And bending fatigue tests are also performed by the rotary bending machine at room temperature.The tensile strength and elastic modulus have been improved up to 38% and 35% by the addition of the reinforcements, respectively. Thermal expansion coefficients of MMCs which is located normal and parralel to the applied pressure are showed slightly different less than 10%. Fatigue strengh of the composite was improved by about 20% compared with that of unreinforced Al alloy. The results of this study will be used to understand the basic fracture behavior of MMCs and eventually to expand the applocation of MMCs as a machine parts undertaken various loadings.

#### Keywords

Metal Matrix Composites;Squeeze Casting Method;Thermal Stability;Thermal Expansion Coefficient;Fatigue Strength