熔丝电弧增材制造技术(Wire arc additive manufacturing,WAAM)凭借着低成本和高效率成为了一种具有潜力的增材制造方式.然而由于增材过程中为了避免热量累积需要在每一层材料沉积后进行冷却,这不仅降低了增材的效率,高温也会影响材料本身和样品的成形.本试验采用冷金属过渡技术(Cold Metal Transfer,CMT)技术进行IN718镍基高温合金薄墙试样的制备.研究不同冷却工艺(常规空冷和辅助水冷)对制备样品的显微组织与力学性能的影响.结果表明,采用辅助水冷制备IN718合金不仅具有更高的增材效率,并且凭借着稳定且快速的散热,使其成形质量好于常规的空冷.由于辅助水冷具有较高的冷却速度和较低的样品温度,抑制其内部的Laves相的生长,使合金内部析出细小的Laves相,而空冷由于散热条件差,高温导致Laves析出并相长大.这导致水冷试样的塑性优于空冷试样.同时由于Laves相产生的第二相强化,水冷试样的强度更高,但伴随着其塑性的降低.本研究不仅能为电弧增材制造IN718合金提高增材效率,且提升了材料的综合力学性能,为后续高效高质量增材制造IN718零部件提供重要指导意义.
Effect of Water Cooling on the Microstructure and Mechanical Properties of IN718 Alloy Manufactured by Wire Arc Additive Manufacturing
Wire arc additive manufacturing(WAAM)has become a promising additive manufacturing method due to its low cost and high efficiency.However,due to the need for cooling after each layer of material deposition to avoid heat accumula-tion during the additive process,this not only reduces the efficiency of the additive,but also affects the material itself and the formation of the sample at high temperatures.This experiment used Cold Metal Transfer(CMT)technology to prepare thin wall specimens of IN718 nickel based high-temperature alloy.Study the effects of different cooling processes(air cool-ing and water cooling)on the microstructure and mechanical properties of prepared samples.The results show that using auxiliary water cooling to prepare IN718 alloy not only has higher additive efficiency,but also with stable and fast heat dissi-pation,its forming quality is better than conventional air cooling.Due to the high cooling rate and low sample temperature of auxiliary water cooling,the growth of Laves phase inside the alloy is suppressed,resulting in the precipitation of small Laves phase inside the alloy.However,due to poor heat dissipation conditions,high temperature in air cooling leads to Laves precipitation and phase growth.This leads to better plasticity of water-cooled specimens than air-cooled specimens.Meanwhile,due to the second phase strengthening generated by Laves phase,the strength of water-cooled specimens is higher,but it is accompanied by a decrease in their plasticity.
wire arc additive manufacturingcold metal transfernickel-based alloysmicrostructuremechanical properties
万方数据
维普
