放电等离子烧结温度对TiB_(2)/Al复合材料结构与性能的影响

Effect of spark plasma sintering temperature on structure and properties of TiB_(2)/Al composites

以铝粉为基体、二硼化钛颗粒为增强体,采用放电等离子烧结(SPS)技术制备TiB_(2)/Al复合材料,研究了不同烧结温度(500、525、550℃)对复合材料的物相组成、致密度、显微硬度、抗拉/抗压性能的影响。结果表明,所制备复合材料主晶相为α-Al,烧结温度高于525℃时析出少量TiB_(2)相;随着烧结温度升高,复合材料的致密度、硬度、抗拉强度和抗压强度均呈现先增大后减小的趋势,伸长率和压缩率则先减小后增大;烧结温度为525℃时,复合材料的综合性能最佳,致密度和显微硬度(HV)分别获得最高值98.57%和49.83,抗拉强度(84.9 MPa)和抗压强度(265.1 MPa)也达到最大值;烧结温度偏高时(550℃),材料内部形成孔洞,拉伸过程中出现穿晶断裂现象。

TiB_(2)/Al composites were fabricated by spark plasma sintering using aluminum powders as matrix and TiB_(2)particles as reinforcement. The effects of different sintering temperatures(500, 525 ℃and 550 ℃) on the phase composition, relative density, microhardness and tensile/compressive properties of the composites were investigated. The results show that the principal phase of these composites isα-Al, and a small amount of TiB_(2)phase precipitates when the sintering temperature is higher than 525℃. With increasing the sintering temperature, the relative density, microhardness, tensile strength and compressive strength of TiB_(2)/Al composites firstly increases and then decreases, while the elongation and compressibility are minished first and then increased. TiB_(2)/Al composite sintered at 525 ℃ has the optimal comprehensive properties, demonstrating the highest relative density and Vickers hardness of98.57% and 49.83, respectively, and the maximum tensile strength of 84.9 MPa and compressive strength of 265.1 MPa. When the sintering temperature is as high as 550 ℃, voids are formed in the bulk material and transgranular fracture occurs during the tensile process.