Al粉含量对汽车用Al_(2)O_(3)粉末热压注成形组织和性能的影响

Influence of Al powder content on the performance of auto Al_(2)O_(3) hot-pressing injection molding core

选择Al粉作为Al2O3粉末的改性剂,测试不同Al粉添加量时Al2O3粉末的收缩率、显微组织结构、力学性能。结果表明:当Al粉添加量变化后,烧结收缩率发生明显改变,宽度上的烧结收缩率最大,厚度方向的最小。随着Al粉添加量的增加,Al2O3粉末试样抗弯强度及密度都明显下降,气孔率增大,Al2O3粉末挠度明显提升,试样结构的孔径也明显增大,并且形成了更大尺寸的孔径。随着Al粉添加量的逐渐增加,氧化铝衍射峰强度也随之升高。未加入Al粉时试样在断口部位形成了一些大颗粒,表现出穿晶断裂的特点;添加Al粉后断口表现为沿晶断裂。

The Al powder was selected as Al2O3 powder material modifier to test the changes of shrinkage,microstructure and mechanical properties of Al2O3 powder material under different addition amounts of Al powder.The results show that the casting shrinkage of the sample changes significantly with the addition of Al powder,in which the casting shrinkage is the largest in the width and the thickness is the smallest.With the gradual increase of Al powder content,the bending strength and volume density of Al2O3 powder sample decreases significantly,the porosity increases significantly,the powder deflection of Al2O3 also increases significantly,the pore diameter of the casting structure also increases significantly,and the pore diameter of a larger size is formed.With the increase of the content of Al powder,the intensity of alumina diffraction peak increases.When Al powder is not added,some large particles are formed at the fracture site,which showes the characteristics of transgranular fracture.The fracture of the material with Al powder is intergranular fracture.