| The fabrication and creep chararteristics of composites reinforced with stainless steel and high carbon steel fibers haute been studied. The Ni-coating, Cu-coating and bear fibers have been tested to examine the effect of fiber surface characteristics. In order to make various fiber volume fraction composite specimen, the liquid casting method has been applied. Creep characteristics such as the rupture time and the steady state creep rate have been investigated in the range of stress with 22.47 to 72.95MPa at 537k. The rupture time is increased with V_f. The stress exponent(n) has been found to be 21.2∼114. In case of V_f 1.6, 2.88%, 100hr rupture stress(δ) was less than theoritical value calculated by the rule-of-mixture(R.0.M). On the other hand V_f 3.52%, shows δ value close to R.O.M, and coated composites were even larger than R. O. M. Severa1 intermetallic compound such as A1Ni, Al₂Cu, Al_5Fe₃and Al_(13)Fe₄in the interface were observed by TEM. These improved wettability of fiber on matrix, and creep strength due to obstruction of dislocation moving. Tested specimen shows dislocation cells at the substructure. The dislocation density decreased from interface to matrix. |
|
