碳纤维和尼龙纤维对TiAl合金型壳退让性的影响

Effect of carbon and nylon fibers on deformability of TiAl alloy shell

为了改善TiAl合金精密铸造用氧化锆陶瓷型壳的退让性,利用电子万能试验机和扫描电子显微镜对添加不同含量碳纤维和尼龙纤维后的型壳退让性进行了测试.结果表明,添加少量碳纤维可以提高型壳湿强度并降低型壳室温和高温干强度,但当所添加碳纤维的质量分数达到10%后,会同时提高型壳的三种强度.当尼龙纤维的质量分数处于10%以内时,型壳三种强度均会降低.当碳纤维的质量分数达到5%时,型壳的湿强度和室温干强度可分别提高51. 9%和20. 7%,高温干强度降低8. 5%,同时改善了型壳的退让性并降低了铸件的裂纹倾向.

In order to improve the deformability of zirconia ceramic shell for the precision casting of TiAl alloy,the deformability of shell with different additions of carbon and nylon fibers was tested with the electric universal tester and scanning electron microscope( SEM). The results showthat a small amount of carbon fiber addition can increase the wet strength of shell,and reduce its dry strength at both room and high temperatures. However,when the mass fraction of added carbon fiber reaches 10%,the three strengths of shell will simultaneously increase. When the mass fraction of nylon fiber is within 10%,the three strengths of shell will all decrease. When the mass fraction of carbon fiber reaches 5%,the wet strength and dry strength of shell at room temperature can respectively increase by 51. 9% and 20. 7%,while the dry strength at high temperature will decrease by 8. 5%,which improves the deformability of shell and reduces the crack trend of castings.