The effects of geometric shape

resisted shrinkage and free shrinkage

sample size on the linear shrinkage ratio of two high Nb-TiAl alloy investment castings were investigated by orthogonal test. The results show that the average linear shrinkage ratio of Ti–45Al–8Nb is 2.12%–3.28%

and the average linear shrinkage ratio of Ti–48Al–7.5Nb is 2.55%–3.39%

and the linear shrinkage ratio of the latter is larger. The linear shrinkage ratio of the resisted shrinkage specimen in the unblocked direction is 44.8%–47.7% higher than that of the free shrinkage specimen. The geometry and size have little effect on the linear shrinkage ratio

and resistance to solidification shrinkage has a greater impact on linear shrinkage ratio. As the sample size increases

the linear shrinkage increases by 100%

but the linear shrinkage ratio gradually decreases to 20%.