Fatigue Properties for Sinter-Hardened Fe-Ni-Mo-Cu Materials
Fe-4Ni-0.5Mo-1Cu powder was selected as raw material, pressed and sinter-hardened at 1135°C for 30 min with rapid cooling. The density varies in the range of 7.24-7.29 g/cm3. Its fatigue properties have been tested in axial loading of alternating tensile/compressive stress at R=-1 with a servo-pulse pump. The fatigue endurance limit was measured to be 260 MPa. The microstructure showed more homogeneous bainite and martensite. Neither Ni nor Mo rich areas were detected. Fractography displayed the fatigue cracks initiated from the pore areas near the surface. A nontypical ductile fatigue striation was found. More dimples occurred on fracture surface due to the plastic deformation, which can prohibit cracking propagation and improve its fatigue properties.
Duk Yong Yoon, Suk-Joong L. Kang, Kwang Yong Eun and Yong-Seog Kim
C. L. Wang et al., "Fatigue Properties for Sinter-Hardened Fe-Ni-Mo-Cu Materials", Materials Science Forum, Vols. 534-536, pp. 677-680, 2007