冷镦锻工艺对Al-TiO_(2)-Gr粉末冶金复合材料力学性能的影响

Effect of cold upsetting process on mechanical properties of Al-TiO_(2)-Gr powder metallurgy composites

以球磨粉为原料,采用粉末冶金法制备了Al+2.5%TiO_(2)+2%Gr,Al+2.5%TiO_(2)+4%Gr,Al+5.0%TiO_(2)+2%Gr,Al+5.0%TiO_(2)+4%Gr铝基复合材料。使用合适的冲头和模具在40 kN液压机中进行压实,然后在电炉中烧结,烧结预制件承受10 kN的增量压缩载荷,直到在自由表面发现裂纹。冷镦成形过程中,复合材料由于变形产生了拉长晶粒。镦锻过程减少了烧结试样中的气孔。对于含2.5%TiO_(2)和2%Gr的复合材料,气孔被补强体封闭和填充,冷镦锻后的气孔数量非常少,TiO_(2)和Gr颗粒的加入提高了复合材料的强度和硬度。对于含有5%的TiO_(2)和2%的Gr颗粒的复合材料,获得了最大硬度值36.14HRB。

Using ball mill powder as raw material,Al+2.5%TiO_(2)+2%Gr,Al+2.5%TiO_(2)+4%Gr,Al+5.0%TiO_(2)+2%Gr,Al+5.0%TiO_(2)+4%Gr aluminum-based composite materials were prepared by powder metallurgy method.The compaction process was carried out in a 40 kN hydraulic press with a suitable punch and die,and then sintered in an electric furnace.The sintered preform was subjected to an incremental compressive load of 10 kN until cracks were found on the free surface.During the cold heading process,the composite material produced elongated grains due to deformation.The upsetting process reduces the porosity in sintered samples.For the composites containing 2.5%TiO_(2)and 2%graphite,the pores are closed and filled by reinforcements,and the number of pores after cold upsetting is very small.The addition of TiO_(2)and graphite particles improves the strength and hardness of the composites.For the composites containing 5%TiO_(2)and 2%graphite particles,the maximum hardness value 36.14HRB is obtained.