The present study aims to analyse of the role of volumetric energy density (VED) in the achievement of denser titanium alloy (Ti6Al4V) through the use of Laser based powder bed fusion (L-PBF) process. Rectangular blocks were fabricated with five different VEDs, namely, 35.07 J/mm³, 40.46 J/mm³, 44.19 J/mm³, 55.11 J/mm³ and 60.45 J/mm³. A highly intensified laser beam causes a faster cooling rate resulting in excessive formation of unstable needle-like martensite (α') phases inside the columnar beta (β) grains. Reduction in scan speed from 990 to 630 mm/sec with constant laser power as 250 W triggered the formation of keyhole pores. Also, a similar kind of observation was noted when the scan speed was reduced from 1270 to 850 mm/sec with constant laser power of 370 W. The sample fabricated with a VED of 44.19 J/mm³ resulted in a minimum fraction of porosity, i.e. 0.04%.The sample fabricated with a VED 44.19 J/mm³ was subjected to solution heat treatment (HT) at 950 °C/1 h and 1050 °C/1 h, i.e. below and above the β transition temperature for the achievement of stable equilibrium microstructure.Solution HT at 950 °C resulted in the growth of thin and thick needles of Widmanstätten α phases followed by water quenching (WQ) and air cooling (AC), respectively. The columnar β grains were disintegrated at 1050 °C leading to the equiaxed grain boundary α along with newly formed α' phases after WQ and lamellar α phases after AC. The findings of the study showed the role of energy densities and post L-PBF HT in the achievement of stable microstructure on Ti6Al4V alloy.

本研究旨在分析体积能量密度 (VED) 在通过使用基于激光的粉末床熔合 (L-PBF) 工艺获得更致密的钛合金 (Ti6Al4V) 中的作用。用五种不同的 VED 制造矩形块，即 35.07 J/mm ³、40.46 J/mm ³、44.19 J/mm ³、55.11 J/mm ³和 60.45 J/mm ³。高度增强的激光束导致更快的冷却速度，导致在柱状 β ( β ) 内部过度形成不稳定的针状马氏体 ( α ') 相）谷物。在 250 W 的恒定激光功率下，扫描速度从 990 毫米/秒降低到 630 毫米/秒，触发匙孔孔的形成。此外，当扫描速度从 1270 降低到 850 毫米/秒且激光功率恒定为 370 瓦时，观察到类似的观察结果。用 44.19 焦耳/毫米³的 VED 制造的样品导致孔隙率最小，即 0.04%。使用 VED 44.19 J/mm ^{3制造的样品在 950 °C/1 小时和 1050 °C/1 小时（即低于和高于}β转变温度）下进行固溶热处理 (HT)稳定平衡微观结构。溶液 HT 在 950 °C 导致 Widmanstätten α细针和粗针的生长阶段之后分别是水淬（WQ）和空冷（AC）。柱状β晶粒在 1050 °C 解体，导致等轴晶界α以及WQ 后新形成的α ' 相和AC 后的层状α相。该研究的结果显示了能量密度和后 L-PBF HT 在 Ti6Al4V 合金上实现稳定微观结构的作用。