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研究了热旋锻和退火处理对精密铸造工业纯钛显微组织和力学性能的影响。铸造样品为典型的含有不同形貌的α相组织;而旋锻样品是缠绞的层状组织。在500°C退火处理不会显著改变样品的显微组织,但在700°C和870°C退火会导致再结晶发生和生成等轴晶组织。铸造棒在近表层生成典型的硬化α层,其最大深度达720μm,最大硬度达HV0.5660。旋锻能使铸造样品的拉伸强度从605MPa增加到895MPa。在500°C退火会导致拉伸强度轻微降低,从895MPa降到865MPa。然而在700°C退火会导致拉伸强度显著下降,从865MPa降到710MPa。当退火温度升高到870°C时,拉伸强度的下降不再明显。铸造和热旋锻样品的断裂应变在0.05~0.12的范围内,而退火后的样品在0.25~0.53的范围。铸态和旋锻态样品表现为脆性解理断裂,而退火态样品为穿晶塑性断裂,伴有韧窝的生成。
The effects of hot swaging and annealing on the microstructure and mechanical properties of industrial pure titanium in precision casting were studied. Cast samples are typically α-phase microstructures with different morphologies; swaged samples are entangled, layered structures. Annealing at 500 ° C did not significantly alter the microstructure of the samples, but annealing at 700 ° C and 870 ° C led to recrystallization and formation of equiaxed grains. The cast rod produces a typical hardened α-layer near the surface with a maximum depth of 720 μm and a maximum hardness of HV 0.5660. Swaging can increase the tensile strength of cast samples from 605 MPa to 895 MPa. Annealing at 500 ° C resulted in a slight decrease in tensile strength from 895 MPa to 865 MPa. However, annealing at 700 ° C resulted in a significant decrease in tensile strength from 865 MPa to 710 MPa. When the annealing temperature is increased to 870 ° C, the decline in tensile strength is no longer significant. The strain at break of cast and hot-swaged samples was in the range of 0.05-0.12, while the annealed samples were in the range of 0.25-0.53. The as-cast and as-swirled samples show brittle cleavage fractures, while the annealed samples are transcrystalline ductile fractures with the formation of dimples.