激光选区熔化TC4钛合金点阵结构压缩性能研究

Compression Performance of TC4 Titanium Alloy Lattice Structures Manufactured by Selective Laser Melting

摘要:

通过增材制造成型复杂晶格结构,实现航空航天结构件的轻量化设计得到越来越多的应用,然而点阵结构设计及其性能评价仍欠缺。本研究采用金刚石结构为基体,以点阵密度、结构形式为目标,设计不同几何参数试样,并以TC4钛合金为对象进行成型。对成型试样进行压缩试验,研究这种结构不同尺寸试样压缩性能的差异,结果表明：金刚石点阵结构试样受到载荷后应力在连接节点位置集中,产生断裂。提高晶胞密度可以缓解应力集中现象,提高比强度,减少晶胞尺寸和添加外壳都可以使应力均匀化,提高性能稳定性。小晶胞尺寸试样对球化现象、孔隙等冶金缺陷较为敏感,造成强度的下降。

Abstract:

More and more applications have been made to realize lightweight design of aerospace parts by additive manufacturing to form complex lattice structures. However, the lattice structure design and its performance evaluation are still lacking. In this study, the diamond structure was used as the matrix, and the specimens with different geometric parameters were designed for forming with TC4 titanium alloy, aiming at lattice density and structure form. Compression tests were carried out on the formed specimens to study the differences of compressive properties between specimens of different sizes. The results show that the stress of the diamond lattice structure specimens will concentrate at the joint position and cause fracture after being loaded. Increasing cell density can alleviate the phenomenon of stress concentration, increase specific strength, reduce cell size and add shell can make the stress uniform and improve the stability. Small cell size specimens are more sensitive to metallurgical defects such as spheroidization and pore, resulting in a decrease in strength.