高能球磨-放电等离子烧结制备双尺度细晶钛

摘要

采用高能球磨和放电等离子烧结技术制备出包含粗晶区和细晶区的双尺度细晶钛，并研究不同球磨时间的钛粉烧结试样的显微组织和力学性能。实验结果表明，随着球磨时间的增加，钛粉烧结试样的显微组织先由粗晶转变为双尺度晶粒，随后又转变为均匀的细晶组织。与单一尺度的粗晶钛和细晶钛相比，双尺度细晶钛具有更好的强度和塑性的组合。在球磨10 h 钛粉烧结后的试样中，细晶区(平均晶粒尺寸为1μm)和粗晶区(晶粒尺寸大于5μm)的体积分数分别为65.3%和34.7%，其压缩强度达到1028 MPa，同时断裂时的塑形应变达到22%。%Bimodal-grained Ti containing coarse and fine grains was fabricated by high-energy ball milling and spark plasma sintering (SPS). The microstructure and mechanical properties of the compacts sintered by Ti powders ball-milled for different time were studied. Experimental results indicated that when the ball-milling time increased, the microstructure of sintered Ti was firstly changed from coarse-grained to bimodal-grained structure, subsequently transformed to a homogeneous fine-grained structure. Compared with coarse-grained Ti and fine-grained Ti, bimodal-grained Ti exhibited balanced strength and ductility. The sample sintered from Ti powders ball-milled for 10 h consisting of 65.3% (volume fraction) fine-grained region (average grain size 1 μm) and 34.7% coarse-grained region (grain size > 5 μm) exhibited a compress strength of 1028 MPa as well as a plastic strain to failure of 22%.