CAJ | 학술논문

采用双步球磨法和放电等离子烧结技术制备细晶Ti-45Al-2Cr-2Nb- 1B-0.5Ta-0.225Y(摩尔分数,％)合金,并研究烧结温度、显微组织和力学性能之间的关系.结果表明:双步球磨粉末的颗粒形状较规则,其颗粒尺寸为20～40 μm,主要由Ti3Al和Ti3A1相组成.放电等离子烧结后的块体由主相TiAl、少量的Ti3Al相及Ti2Al和TiB2相组成.当烧结温度为900℃时,烧结块体获得的主要组织是等轴晶组织,等轴晶粒尺寸大多数在100～200nm的范围内,合金的压缩断裂强度为2769 MPa,压缩率为11.69％,抗弯强度为781 MPa;当烧结温度为1000℃时,等轴晶粒明显长大,TiB2相明显增多,合金的压缩断裂强度为2669 MPa,压缩率为17.76％,抗弯强度为652MPa.随着烧结温度的升高,合金的维氏硬度由658降低到616.压缩断口形貌分析表明,合金的断裂方式为沿晶断裂.
채용쌍보구마법화방전등리자소결기술제비세정Ti-45Al-2Cr-2Nb- 1B-0.5Ta-0.225Y(마이분수,％)합금,병연구소결온도、현미조직화역학성능지간적관계.결과표명:쌍보구마분말적과립형상교규칙,기과립척촌위20～40 μm,주요유Ti3Al화Ti3A1상조성.방전등리자소결후적괴체유주상TiAl、소량적Ti3Al상급Ti2Al화TiB2상조성.당소결온도위900℃시,소결괴체획득적주요조직시등축정조직,등축정립척촌대다수재100～200nm적범위내,합금적압축단렬강도위2769 MPa,압축솔위11.69％,항만강도위781 MPa;당소결온도위1000℃시,등축정립명현장대,TiB2상명현증다,합금적압축단렬강도위2669 MPa,압축솔위17.76％,항만강도위652MPa.수착소결온도적승고,합금적유씨경도유658강저도616.압축단구형모분석표명,합금적단렬방식위연정단렬.
A fine-grained TiAl alloy with a composition of Ti-45Al-2Cr-2Nb-1 B-0.5Ta-0.225Y (mole fraction,％) was prepared by double mechanical milling(DMM) and spark plasma sintering(SPS).The relationship among sintering temperature,microstrueture and mechanical properties was studied.The results show that the morphology of double mechanical milled powder is regular with size in the range of 20 40 μm and mainly composed of TiAl and Ti3Al phases.The main phase TiA1 and few phases Ti3Al,Ti2Al and TiB2 were observed in the SPScd alloys.For samples sintered at 900 ℃,the equiaxed crystal grain microstructure is achieved with size in the range of 100-200 nm.With increasing the SPS temperature from 900 ℃ to 1000 ℃,the size of equiaxed crystal grain obviously increases,the microhardness decreases from HV658 to HV616,and the bending strength decreases from 781 MPa to 652MPa.In the meantime,the compression fracture strength also decreases from 2769 MPa to 2669 MPa,and the strain to fracture in compression increases from 11.69％ to 17.76％.On the base of analysis of fractographies,it shows that the compression fracture transform of the SPSed alloys is intergranular rupture.