Study On Preparation And Friction And Wear Properties Of Ti₂SnC/ZA27 Composites

Zinc aluminum alloy has good mechanical properties, good friction and wear properties, low cost of raw materials; layered ternary compound Ti2SnC is a combination of the excellent properties of metals and ceramics, as a novel particle reinforced phase is used for strengthening of Zn-Al alloy was prepared by higher performance of matrix composite materials. In this study,different compositions ofTi2SnC/ZA27 composites are prepared by different sintering conditions.The relative density,hardness,bending strength, tensile strength,friction and wear performance were tested in order to do some exploratory experiments. The microstructure and phases of the composites were analyzed by using X-ray diffraction, scanning electron microscopy and EDS. The results showed that:(1) Sintering temperature of the Ti2SnC and the heating rate had an influence on the purity of Ti2SnC powders. The results indicated that the purity of the Ti2SnC powders was highest after holding 2h in the vacuum when heating the Ti/Sn/C powders in the ratio of 2:0.9:0.85 to 1260℃ at the heating rate of 5’C/min.(2)Properties of Ti2SnC/ZA27 composites are influenced by the contents of the enhanced phase. At the sintering temperature of 870 C, holding time 1h, under the pressure of 30MPa, with the increase of Ti2SnC content, the hardness of the composites increased, and the hardness of 40vol%Ti2SnC composites was 1.21GPa; The relative density decreased with the addition of the reinforcing phase, The density of 10vo%Ti2SnC composites was closest to that of ZA27 alloy, which was 94.9%; The mechanical properties increase with the increase of the content of the reinforced phase firstly increase and then decrease.30vol%Ti2SnC is the composite material with the best tensile strength and bending strength,308MPa and 509MPa respectively.(3)Properties of Ti2SnC/ZA27 composites are influenced by the sintering temperature. Under the condition of pressureless sintering, The relative density, hardness, tensile strength and bending strength of 30vol%Ti2SnC composites increase with the increase of sintering temperature, When the sintering temperature is 870, the relative density is 90.9%, the hardness is 804MPa, the tensile strength and bending strength are 262MPa and 361 MPa, respectively.(4)Added Ti2SnC reinforced particles in the ZA27 matrix can effectively improve the wear resistance of the composites and reduce the friction coefficient. In 10-30vol.%, with the increase of Ti2SnC particles reinforced phase volume fraction, the friction and wear properties of the composites continuously improved. In the experimental conditions of sliding speed 3m/s, normal pressure 0.2 MPa, compared with the ZA27 matrix, the friction coefficient of 30vol.% Ti2SnC/ZA27 composites fell down to 41% and the wear rate decreased to 62.5%.SEM investigating show that sticking friction,Oxidize friction and grain-abrasion are all taking effect in the friction process of Ti2SnC/ZA27 and the sticking friction is the most important friction form.