Increasing the solidification velocity ( V V) would increase the critical temperature gradient G c G c because G c G c is directly proportional to V V. This means that a higher V V requires a larger G T G T to avoid constitutional undercooling. Conversely, decreasing V V would lower G c G c , making it easier to maintain stability with a given G T G T . Therefore, if V V increases, the likelihood of constitutional undercooling also increases, unless G T G T is adjusted accordingly