粉末冶金制备换热管用HAl77-xTi铝黄铜合金及其性能表征

Characterization of HAl77-xTi aluminum brass alloy for heat exchange tube preparation by powder metallurgy

对Ti与HAl77铝黄铜建筑粉末充分混合,再对其实施放电等离子烧结及热挤压处理,分析不同固相烧结工艺下,在铝黄铜内加入Ti时引起的物相结构与组织分布状态的变化,并对试样的界面组织与力学强度进行了测试。研究结果表明:未添加Ti时,在HAl77基体内存在α与β两种组织相。加入Ti元素后在HAl77基体组织内形成了许多弥散态的第二相晶粒,当Ti含量逐渐增大后,得到的第二相颗粒也持续变多,呈现不规则的外形结构。当Ti的加入量逐渐增大后,合金试样各项力学性能参数发生了线性变化,铝黄铜获得了更优的力学性能;并且微裂纹数量降低,形成了更多韧窝并在断口部位呈均匀分布。在外力作用下,位错将会使Ti与Cu_(2)Ti_(4)O颗粒发生作用,阻碍基体变形,显著提高合金强度。

Ti and HAl77 powder were fully mixed and then subjected to discharge plasma sintering treatment and hot extrusion.The changes of phase structure and microstructure distribution caused by Ti addition in aluminum brass under different solid-phase sintering processes were analyzed,and the interface microstructure and mechanical strength of samples were tested.The results show that there are two kinds of microstructure phases in HAl77 matrix without adding titanium.After the addition of Ti element,a number of dispersed second-phase grains are formed in the HAl77 matrix.When the Ti content gradually increases,the second-phase particles obtained also continue to increase,showing an irregular shape structure,the mechanical properties of the alloy samples change linearly,the mechanical properties of aluminum brass were improved.In addition,the number of microcracks decreases,forming more dimples and presenting uniform distribution at the fracture site.Under the action of external force,the dislocation will make Ti and Cu_(2)Ti_(4)O particles interact,hinder the deformation of the matrix,and significantly improve the alloy strength.