工艺参数设置和厚度对电子束熔融加工的Ti-6Al-4V的微观结构的影响

Effect of Process Parameters Settings and Thickness on Microstructures of EBM Produced Ti-6Al-4V

摘要:

本文研究了试件尺寸和工艺参数（电子束强度，扫描速度，焦点偏移量和扫描长度）对EBM加工的Ti-6Al-4V微观结构的影响。通常，可以观察到EBM加工的Ti-6Al-4V的微观结构是由原始β相的柱状晶粒组成。在柱状晶粒内部观察到典型的（α+β）结构，即魏氏体α片和在细小的α晶粒的界面上形成的杆状β相。还发现沿原始β柱状晶粒的晶界形成α层晶界。随着试件厚度，电子束能量密度和扫描长度的增加，先前的β柱状晶粒的直径增大，并且生长的方向与加工方向一致。同时，柱状晶粒直径也随着高度的增加而减小。随着厚度和电子束能量密度的增加，α片会变得更粗大。

Abstract:

In the current study, the effect of sample dimensions and process parameters (beam current, scan speed, offset focus and scan length) of EBM system on microstructure of the EBM built Ti-6Al-4V has been investigated. In general, it can be observed that the microstructures of EBM built Ti-6Al- 4V consist of columnar grains of prior β phase. Inside the columnar grain typical (α+β) structures namely Widmanst?tten α platelets with rod like β phase formed on the interfaces of the fine α grains has been observed. Grain boundary α layer is found to be formed along grain boundary of prior β columnar grain. With increasing thickness of the test slab, beam energy density and scanning length, the diameter of prior β columnar grain increases and they follow the build direction. The columnar grain diameter also decreases with increase in height. With increasing thickness and beam energy density α platelets get coarser.