Microstructural characterization and wear behavior of in situ TiC/7075 composites synthesized by displacement reactions and spray forming
Microstructural characterization and wear behavior of in situ TiC/7075 composites synthesized by displacement reactions and spray forming
复制标题
DOI：
10.1016/j.msea.2010.09.103
复制
发表时间：
2011-07
期刊：
影响因子：
6.4
通讯作者：
B. Yang;Gui-Sheng Gan;Lu Yang;Miao Sun;Haibo Zhang;Z. Fang
中科院分区：
文献类型：
--
作者：
B. Yang;Gui-Sheng Gan;Lu Yang;Miao Sun;Haibo Zhang;Z. Fang
提出了一种新的原位反应法制备TiC/7075复合材料的方法。该技术为克服喷射成形过程中增强颗粒先在熔融金属中形成，再注入熔滴的喷射锥中的损失和团聚问题提供了一种新的途径。实验结果表明，在Ti - C - al复合材料中采用适当的Ti:C摩尔比可以完全避免条状或矩形状Al3Ti的存在，这不仅对断裂韧性有害，而且对组织的稳定性也有害。从热力学的角度解释了TiC/7075复合材料中Al3Ti相形成或缺失的机理。7075合金的微观组织变化可以从原子扩散的角度来理解。磨损结果表明，随外加载荷的增加，喷射成形7075合金及其复合材料的磨损率增大。在较高的载荷下，7075合金的耐磨性优于复合材料。这是由于复合材料比基体合金的微裂倾向增加。
A novelin situreaction technique is developed to prepare TiC/7075 composites. This technique provides a new approach overcoming the problems of loss and agglomeration of reinforcement particles when they arein situformed in a molten metal first and then injected into the spray cone of molten droplets during the spray forming process. Experimental results have shown that the presence of strip or rectangular-like Al3Ti, which is detrimental not only to the fracture toughness, but also to the stability of the microstructure, can be avoided completely from the final product by using a proper Ti:C molar ratio in the Ti–C–Al performs. The mechanisms of formation or absence of Al3Ti phase in the TiC/7075 composites are explained based on thermodynamics of the system. The modification of the microstructure of the spray-formed 7075 alloy can be understood in the light of atomic diffusion. The wear results showed that the wear rates of the spray-formed 7075 alloy and its composites increased with applied loads. At higher applied loads, the 7075 alloy exhibited superior wear resistance than that of the composites. This is attributed to increased microcracking tendency of the composites than the matrix alloy.