【摘要】 为提升激光增材IN718合金部件的力学性能和服役温度，按梯度增加Ti+Al含量制备了五种改进型IN718激光增材样品，采用万能实验机、SEM、XRD和JMatpro软件等研究了样品的常温和高温力学性能及组织结构。结果表明，随着Ti+Al含量的增加，γ′相占比逐渐上升，样品室温强度增大而延伸率明显下降。当Ti+Al含量增加到7.6%时，样品中的γ′析出相占比是γ相的5倍，硬度为55.6 HRC,因脆性相的大量析出导致裂纹萌生；经1 100℃×1 h+850℃×8 h热处理后的样品在850℃时的强度随Ti+Al含量的增加先升高后降低，Ti+Al含量为5.6%时其高温屈服强度和延伸率达到最大值，分别为553 MPa和12%,且各向同性，此时γ′析出相和γ相占比接近，分别为41.5%和39.9%。在后续研究中，可将标准IN718合金中的Ti+Al含量提高到5.6%,恰当利用γ′强化获得优良的高温力学性能和激光增材工艺相容性。更多还原

【Abstract】 To improve the mechanical properties and service temperature of laser additive IN718 alloy components, five improved IN718 laser additive samples with the gradient increase in Ti+Al content were prepared.The mechanical properties at room temperature and high temperature and microstructure of the samples were studied by universal testing machine, SEM,XRD,and JMatpro software.The results indicate that as the Ti+Al content increases, the proportiaon of γ′ phase gradually rises, with an increase in room temperature strength and a significant decrease in elongation.When the content of Ti+Al reaches 7.6%,the proportion of γ′ precipitated phase is 5 times that of γ phase and the hardness is 55.6 HRC.Then the abundant precipitation of brittle phases results in the initiation of cracks.After undergoing 1 100 ℃×1 h+ 850 ℃×8 h heat treatment, the high-temperature strength of the samples at 850 ℃ initially increases and then decreases with the increasing Ti+Al content.And when the content of Ti+Al arrives at 5.6%,the high-temperature yield strength and elongation of the samples reach the maximum value of 553 MPa and 12%,respectively, showing consistency in all directions.Meanwhile, the proportions of γ′ precipitated phase and γ phase are close(41.5% and 39.9%,respectively).In subsequent research, the Ti+Al content in standard IN718 alloy can be increased to 5.6%,and properly using γ′ strengthening can obtain excellent high-temperature mechanical properties and compatibility of laser additive process.更多还原