Abstract
The purpose of the present work is to clarify the relationship between the internal and external notch factors which are concerned with the infiltrating time and ratio, non-metallic inclusions and the matrix hardness, and the fatigue strength of Cu-infiltrated sintered iron compacts.
The results obtained were as follows:
(1) When pores of iron skeleton were infiltrated with copper or silver, the calculated internal notch factors of infiltrated specimens reduced remarkably. Both their internal and external notch factors increased gradually with increasing the formation of Fe-Cu alloy phase during infiltrating.
(2) The calculated internal notch factors of Cu-infiltrated specimens increased, while the external notch factors of them decreased reversely with decreasing the infiltrating ratio.
(3) When the iron skeleton containing essentially some non-metallic inclusions was infiltrated with copper, both its internal and external notch factors increased.
(4) The calculated internal notch factors of Cu-infiltrated specimens increased greatly by age-hardening, but their external notches after age-hardening affected only slightly their fatigue strengths. This might be reasoned that the sensitivity for the internal notch of them increased with increasing the matrix hardness due to age-hardening.
