Mechanical characterization of cp-Ti produced by investment casting

精密铸造工业纯Ti的力学性能(英文)

The influence of hot swaging（SW） and annealing treatment on microstructure and mechanical properties of commercially pure titanium produced by investment casting was evaluated.The as-cast samples showed a typical microstructure consisting of a variety of α-morphologies,while the hot swaged samples exhibited a kinked lamellar microstructure.Annealing at 500 °C did not significantly change this microstructure while annealing at 700 and 870 °C led to recrystallization and formation of equiaxed microstructures.The cast bars exhibited a typical hard α-layer in near-surface regions with a maximum depth and maximum hardness of 720 μm and HV0.5 660,respectively.Due to SW,the tensile strength of the as-cast material drastically increased from 605 MPa to 895 MPa.Annealing at 500 °C decreased the tensile strength slightly from 895 to 865 MPa while annealing at 700 °C led to a further pronounced drop in tensile strength from 865 to 710 MPa.No additional decrease in tensile strength was noticed with increasing the annealing temperature from 700 to 870 °C.The true fracture strain of the as-cast and hot swaged samples was in the range of 0.05 to 0.12,while the annealed samples showed values in the range of 0.25 to 0.53.In addition,the as-cast and hot swaged samples revealed a brittle cleavage fracture surfaces.However,the annealed samples showed a transgranular ductile fracture with formation of dimples.

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。