Investigation Of PM TiC_p/30CrNi4Mo Steel Matrix Composites

With rapid development of science and technology, the requirements of materials have been getting higher and higher, and composites have been the direction of modern materials development. Currently, there is a few research on the steel matrix composites, which lags far behind light metal matrix composites. As a result of the integration of characteristics of the steel and ceramic particles, hard ceramic particle reinforced steel matrix composites possess both excellent mechanical properties, and good wear resistance and high temperature performance, for which it can be an excellent structural material. Previous studies have focused on the wear resistance of steel matrix composites mainly, but in recent years, the fabrication of high strength and toughness steel matrix composites with lightweight have got more and more researchers’ attentionIn this paper, powder metallurgy technology was used. Ti Cp/30 Cr Ni4Mo composites were prepared by hot pressing(HP), hot isostatic pressing(HIP) and spark plasma sintering(SPS). Effect of different process parameters and Ti C particulate content on microstrcucture, physical and mechanical properties and wear properties were investigated by metallurgical microscope, X-ray diffraction, SEM, TEM and so on. Results are as follows:1 Fine and uniform composite powders with narrow particle size distribution range can be obtained through 20 h high energy ball milling. The particle size distribution is 1-40 m. There are scarcely effects of balling time and Ti C particulate content on the phase of the composite powders.2 xTi Cp/30 Cr Ni4Mo(x=0,5,10,15,20) composites were prepared by HP. Microstructure of HP composites are fine lamellar pearlite, ferrite and few residual austenite. The composites with 15% Ti C particulate possess the best comprehensive mechanical properties, of which the density, relative density, hardness, tensile strength, compressive strength and compression ratio are 7.05g/cm3, 97.8%, 47.6HRC, 1161 MPa, 1740 MPa, 23%, at the same time, its wear wear resistance property increased 6 times compared with matrix material without added Ti C particle. The wear resistance property improved with Ti C content increasing. The wear resitance of 20 Ti Cp/30 Cr Ni4Mo composites is more competitive at high velocity under high load. The wear forms of composites under different loads are slight abrasive wear.3 15 Ti Cp/30 Cr Ni4Mo composites were prepared by HIP. The microstructure of HIP composites are fine lamellar pearlite, ferrite and few residual austenite. Ti C particulates are distributed in the matrix, with a typical- structure. The HIP composites possess great comprehensive properties, of which the density, relative density, hardness, tensile strength, elongation, compressive strength and compression ratio were 7.18g/cm3, 99.7%, 49.1HRC, 1266 MPa, 4.0%, 1840 MPa, 30%. The tensile strength of HIP composites still reach 1135 MPa at 400, showing good high temperature mechanical property. However the strength start to decreased sharply after 500, the strength is just 561 MPa at 600. The strength and elongation of HIP composites reach 1325 MPa and 4.6% after water quench at 950 and temper at 520.4 15 Ti Cp/30 Cr Ni4Mo composites were prepared by SPS at different temperatures. The densification process of 15 Ti Cp/30 Cr Ni4Mo composite powders is composed of 5 stages. Microstructure of SPS composites at different temperatures are fine lamellar pearlite, ferrite and few residual austenite, with Ti C particulates distributed uniformly in the matrix. The SPS composites reach the best physical mechanical properties when the sintering temperature is 1050, of which the density, relative density, hardness, tensile strength, compressive strength and compression ratio are 7.11g/cm3, 98.8%, 56.3HRC, 1240 MPa, 2300 MPa and 12.6%.