Use of 450-808 nm diode lasers for efficient energy absorption during powder bed fusion of Ti6Al4V
Use of 450-808 nm diode lasers for efficient energy absorption during powder bed fusion of Ti6Al4V
复制标题
DOI：
10.1007/s00170-021-06774-4
复制
发表时间：
2021-02-21
影响因子：
3.4
通讯作者：
Mumtaz, Kamran
中科院分区：
文献类型：
--
作者：
Alsaddah, Mohammed;Khan, Ashfaq;Mumtaz, Kamran
添加制造工艺选择性激光熔化(SLM)使用粉末床熔化方法来完全熔化金属粉末层并创建3D组件。目前的SLM系统配备了单个或多个(最多四个)高功率振镜扫描红外光纤激光器，工作在1064 nm的固定波长。在该波长下，大多数金属发生有限的激光能量吸收(例如，铝合金的吸收率低于10%，钛的吸收率为50%-60%)。1064 nm激光的低吸收要求更高的激光功率，以补偿由于反射率而造成的能量损失，并完全熔化原料材料。这使得在当前的粉末床聚变SLM系统中使用1064 nm激光的能源效率低下。此外，由于物理空间要求和高昂的经济成本，在SLM系统架构中扩大这些激光光源的潜力有限，这进一步限制了当前最先进的SLM生产率。这项研究使用低功率、高度可扩展的光纤耦合半导体激光器光源，以及使用二极管区域熔化(DAM)方法研究较短的激光波长(450-808 nm)对材料吸收和加工效率的影响。研究发现，当加工Ti6Al4V时，450 nm激光的吸收比808 nm激光高11%，比1064 nm激光高14%。当激光功率仅为3.5W时，450 nm和808 nm的最高粉床温度分别为1920℃-0和1760℃-0。由于DAM过程扫描粉床的速度，熔池冷却速度(750-1400C/S)比传统SLM(10(5)-10(60)C/S)慢得多。这鼓励了形成的Ti6Al4V成分中的β相的发展。低功率、低成本、高度紧凑的短波长半导体激光器是未来粉末床熔融添加剂制造系统的可行能源，具有使用DAM方法扩大生产率的潜力。
The additive manufacturing process selective laser melting (SLM) uses a powder bed fusion approach to fully melt layers of powdered metal and create 3D components. Current SLM systems are equipped with either single or multiple (up to four) high-power galvo-scanning infrared fibre laser sources operating at a fixed wavelength of 1064 nm. At this wavelength, a limited laser energy absorption takes place for most metals (e.g. alloys of aluminium have less than 10% absorption and titanium 50-60% absorption). The lower absorption of 1064-nm laser sources requires higher laser powers to compensate for the loss of energy due to reflectivity and fully melt the feedstock material. This makes the use of 1064-nm lasers within current powder bed fusion SLM systems energy inefficient. Further to this, there is limited potential for scale-up of these laser sources within an SLM system architecture due to physical space requirements and high economic cost, placing further limitations on current state-of-the-art SLM productivity. This research investigates the use of low power, highly scalable fibre coupled diode laser sources and the influence of shorter laser wavelengths (450-808 nm) on material absorption and processing efficiency using a diode area melting (DAM) approach. It was found that when processing Ti6Al4V, absorption was 11% higher using 450-nm lasers when compared to using 808-nm lasers and 14% higher than 1064-nm lasers. The maximum powder bed temperature for irradiation at 450 nm and 808 nm was 1920 C-0 and 1760 C-0 respectively when using only 3.5 W of laser power. Due to the speed at which the DAM process scans the powder bed, the melt pool cooling rate was much slower (750-1400 C-0/s) than traditional SLM (10(5)-10(6 0)C/s). This encouraged the development of beta phases within the formed Ti6Al4V component. The low power, low cost, highly compact short wavelength diode laser is viable energy source for future powder bed fusion additive manufacturing systems, with potential for productivity scale-up using a DAM methodology.