The Mechanical Properties And Abrasion Resistance Of Al / Al> 3 P / Steel Composites Were Investigated

As the society develops, the overcapacity of steel becomes an emerging issue, and the simple steel materials are more and more difficult to fill in the needs of nowadays industry requirements. The modern industry requires the Steel to be able to withstand high temperature and speed, to be wearable as the coexisting conditions. The solution lies in the exploitation and research of the particle reinforced steel matrix composites. WC as the most commonly used reinforcement particles, which is widely applied in industry. But because of the relative high cost of the raw steel material, and a considerable gap in linear expansion coefficient between WC and steel material. It’s easy to form the micro-crack on the interface of particles and matrix if the particles size is over large. So Al2O3 became a research focus in wear-resistant area, based on its better chemical stability, cheaper price and extensive source. A number of studies have been showed that Fe-Cr phase was formed at the interface of Al2O3 particles and iron matrix by adding Cr activation substance, it can not only improve the wettability of Al2O3 particles and steel matrix, but also improve the mechanical properties and corrosion-resistant of matrix. However, there are no elaborate research results yet about how the content change of Cr makes a difference on the Al2O3p/steel composites to wettability, mechanical properties and wear resistance.Different qualities of FeCr69C0.25 particles and Cr particles have been added into this paper, by the method of squeeze casting, the Al2O3p/steel compositions have been bringing into manufacture. Under the research of the influence of adding different species and qualities Cr activation substance to interface and substrate organization, and in comparable with the hardness, bending strength, and impacting abrasive wear and static load abrasive wear from Al2O3p/Hadfield steel compositions.First, the Al2O3p/Hadfield steel compositions, which are manufactured by squeeze casting, there are some cracks in the matrix, but large gap in between the interface of particles and substrate. The micro mar hardness was 273.OHV, the macro hardness was 31HRC and bending strength was 163.4MPa.Cr particles (16.6%,22.7% and 36.3% wt of Al2O3) are added in the preform and composites were manufactured by the squeeze casting. The results of hardness showed that, the more Cr particles are being added, the stronger the micro hardness will be, which is increased by solid solution and dispersion strengthening. But the more Cr particles are being added, the weaker the macro hardness will be, which is caused by the strengthening the endothermic effect from molten steel, and defects appeared in the matrix.In order to make the Cr activation substance to be completely melted into matrix, so the FeCr69C0.25 particles (16.5%,36.0%,52.9% and 88.7% wt Al2O3) are added in the pre-form.16.5% FeCr69C0.25 particles in the matrix were completely melted, the interface of particle and matrix was well conditioned. The hardness of micro matrix was 380.6HV, the macro hardness was 30.4HRC. The composites added 36.0% FeCr69C0.25 particles, lots of FeCr69C0.25 particles have not been completely melted, dispersion strengthening effect was increased and macro hardness decreased causing fluidity of molten steel was decreased, the micro-hardness was 475.9HV, and macro-hardness was 25.5HRC. The composites of added 88.7% FeCr69Co.2sparticles, plenty of them which have been left on the edge of Al2O3 particles have not been completely melted, the micro-hardness was 421.4HV, and macro-hardness was 28HRC. The composites added 52.9% FeCr69C0.25 particles had the marten site and austenite matrix after heat-treated, the micro-hardness was 574.5HV and macro-hardness was 42.2HRC.The bending strength of Al2O3p/steel composites which added FeCr69C0.25 particles were higher than Al2O3p/Hadfield steel composites, with increase of the qualities of FeCr69C0.25 particles, matrix toughness was reduced and the bending strength decreased. Along with 16.5% and 88.7% FeCr69C0.25 particles added into the Al2O3p/steel compositions, the bending strength of Al2O3p/Hadfield steel compositions increased correspondingly 54.8% and 24.4%.Except the Al2O3p/4Crl3 steel composites, the impact abrasive wear resistance of the Al2O3p/steel composites with FeCr69C0.25 particles added were better than Al2O3p/Hadfield steel composites because of the Al2O3 particles flaking. The composites with 88.7% FeCr69C0.25 particles added, due to the decreasing volume percent of Al2O3 and the increasing of matrix, the abrasive resistance of it has been increased 61% than the Al2O3p/Hadfield steel composites. At the same time due to the poor toughness of Al2O3p/4Crl3 steel composites, the abrasive resistance stayed the lowest.Because of the high macro hardness and micro hardness after hardening dispose, the Al2O3p/4Crl3 steel composites and Al2O3p/Hadfield steel composites both turned out the best static load abrasive resistance. Meanwhile, the compositions with 16.5%, 36.0% and 88.7% FeCr69C0.25 particles turned out relatively poor abrasive resistance due to the soft matrix.