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基于物质表面扩散和蒸发－凝结的经典理论，对板状晶粒不稳定外形的演变过程进行了有限元模拟结果表明，热蚀沟角θ＝０（无内晶界）时，板状晶粒将直接圆柱化；当内晶界存在时，存在一临界热蚀沟角θｍｉｎ；当θ＞θｍｉｎ时，板状晶粒沿晶界分离。晶粒外形参数β与θｍｉｎ存在关系式：θｍｉｎ＝４．８３６＋４２．９４ｅ［－（β－１．６１）／１．４７８］＋６１．９０ｅ［－（β－１．６１）／９．７３４］．端部初始形状对板状晶粒不稳定外形演变影响甚小，当β＞１０时，可完全忽略．表面原子扩散运动度 Ｍ和表面能γｓ只影响演变时间。
Based on the classical theory of material surface diffusion and evaporation-condensation, the finite element simulation of the evolution of the unstable grain shape of plate-shaped grains shows that when the angle θ = 0 (without internal grain boundaries), the plate-like grains Will be directly cylindrical; when the inner grain boundary exists, there is a critical hot etching gutter angle θmin; when θ> θmin, the plate-like grain separates along the grain boundary. The relationship between the grain shape parameter β and θmin is: θmin = 4.836 + 42.94e [- (β-1.61) /1.478] + 61.90e [- (β-1.61) /9.734]. The initial shape of the tip has little effect on the unstable shape evolution of the plate-like grains. When β> 10, it can be completely neglected. Surface atom diffusion mobility M and surface energy γs only affect the evolution time.