【摘要】 用真空惰性气体雾化法(Vacuum induction melting gas atomization, VIGA)和等离子旋转电极雾化法(Plasma rotating electrode process, PREP)制备ЭП741预合金粉末，然后用热等静压技术(1200℃/140 MPa/3 h)制备出ЭП741粉末合金。用扫描电镜观察并分析了这种粉末合金中的夹杂、原始颗粒边界(PPBs)等缺陷的形成，研究了缺陷对其力学性能的影响，并与粉末变形合金(粉末冶金制坯+热变形)比较。结果表明，用PREP工艺制备的ЭП741粉末更洁净，没有明显的夹杂，成形合金的力学性能优于VIGA粉末的成形合金。ЭП741粉末中的PPBs是ЭП741粉末合金与粉末变形合金力学性能不同的主要原因。在室温和650℃，PPBs恶化了ЭП741粉末合金的力学性能，使其拉伸性能比粉末变形合金的低。在-196℃，PPBs延长了合金中裂纹的扩展路径，减弱了其对力学性能的恶化，使粉末合金的低温抗拉强度和延伸率的平均水平略高于粉末变形合金。更多还原

【Abstract】 Two types of ЭП741 pre-alloyed powder were prepared via vacuum induction melting gas atomization(VIGA) technique and plasma rotating electrode process(PREP) respectively. Then with the pre-alloyed powders, ЭП741 alloy was prepared via hot isostatic pressing(HIP) by 140 MPa at 1200 ~oC for 3 h. In the obtained ЭП741 pre-alloyed powders, there were defects such as inclusions and prior particle boundaries(PPBs) etc., as well as changes in the mechanical properties of the HIPed alloy caused by these defects. Hence, the above matters were systematically assessed by mean of scanning electron microscopy(SEM), while taking the deformed powder metallurgy alloy(PM billet + hot deformation) as a calibration. Results show that the PREP powder exhibited higher purity and fewer inclusions, and the mechanical properties of the HIPed alloy with PREP powder are better than those of the HIPed alloy with VIGA powder. It follows that the PPBs may primarily contribute to the differences in mechanical properties between the HIPed alloys and the deformed PM alloy. Furthermore, PPBs may deteriorate the mechanical properties of HIPed alloys both at room temperature and 650 ~oC, and the tensile properties of HIPed ЭП741 alloys are lower than those of deformed PM alloy. Notably, at cryogenic temperature(-196 ~o C), the PPBs can extend the crack propagation paths, and thus the effect of PPBs on mechanical properties is weakened. In summary, the average levels of tensile strength and elongation of the HIPed alloys are better than those of the deformed PM alloy.更多还原