•The trace angle of α laths has been defined according to orientation-trace method.•The morphology of α laths produced by 〈100〉 fiber texture has been investigated.•The transformed α laths form a cross configuration due to variant selection. The microstructure morphology of transformed α is controlled by the crystallographic orientation of its parent β grain. In the fusion zone of an electron beam welded joint of TC25G titanium alloy, the columnar β grains exhibited a {001} 〈100〉 cube texture, in which four kinds of α laths with two main growth (trace line) directions formed after post-welded heat treatment. According to the numerical simulation by an orientation-trace method, the trace angle of α laths mainly distributed across the ranges of 40˚-60˚ and 120˚-140˚ in the β matrix with 〈001〉 fiber texture, thus the microstructure morphology of transformed α naturally tended to form cross configurations with two nearly perpendicular α laths.