| Ceramic particles reinforced iron matrix composite materials is enhanced through adding carbide particles, at home and abroad. In contrast, Al2O3particles have better advantages in cost and performance. However, wettability between the Al2O3particles and the steel is poor, and there are some question in the steel, such as high melting point, viscosity and the fast cooling speed etc, which bring the preparation of Al2O3p/steel matrix composites to more difficulty..Based on the above analysis, this paper bring forward that Al2O3p/steel composite is prepared by the squeeze casting technology under condition of low thermal conductivity mould. A layer of thicker ceramic insulation coating is attached to inner surface of the mold and using ceramic material low thermal conductivity, good thermal stability maintain the temperature of the liquid steel. Join the activation Ti element into the Precast body improve the wettability of molten steel and Al2O3particles and the interface bonding strength.Thus infiltration method of liquid steel immerse in Al2O3body is realized under a combination of extrusion pressure, the high temperature of liquid steel and action of Precast body.The results show that:Al2O3p/40Cr composites with6mm in thickness and were successfully fabricated with12MPa. The microstructure is compact, the grains of the matrix are fine, uniform particle size distribution, interface bonding tightly, without any other casting defects such as shrinkage cavity and shrinkage macro interface of gradient composite material excessive continuous and natural. The macro hardness of base material is higher than composite layer by11.3%after heat treatment. Illustrate A2O3p/steel composite material interface combined with the weak, poor mechanical properties are the main problems of composite materials.Study on40Cr matrix composites reinforced by15%Ti element activated alumina particles perform:TiC compound is generated in the matrix microstructure and micro interface of composite outer layer, the matrix consists of pearlite and ferrite. But TixSiy compound is generated in the matrix microstructure and micro interface of composite inner layer, the matrix consists of ferrite. There are a-Fe、Fe3C、Al2O3、 TiCand TixSiy in activation of precast body Al2O3p/40Cr matrix composites.For reducing the influence of the other alloying elements and analyzing the function of Ti element,45steel which has extensive use, great performance and less content of alloy elements is selected as base material. Al2O3p/45steel composite materials and5%Ti element activated Al2O3p/45steel composite materials were prepared, in the organization, their impregnation effect were as well as Al2O3p/40Cr steel composite materials. This experiment studied friction and wear performance of these two kind’s composite materials which were in different speed and load conditions. The results show:As the speed and load increasing of wear and tear of the two composites gradually increased. However, friction coefficient has gradually reduced. From the comparison of the two kinds of material abrasion loss, the former is slightly larger than the latter, which mean Ti element improve the interface bonding strength. Ti could improve the wear resistance of Al2O3p/45steel composite materials. The two kinds of material wear form are from abrasive wear gradually converted to oxidation and adhesion, eventually lead to fatigue. And a lot of O, W, V, Cr elements were found on the wear specimen surface. |
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