Ferritic-martensitic (F/M) HT9 along with fully ferritic HT9 specimens were irradiated using self-ions to 600 peak displacement-per-atom (dpa) at 450 °C. To investigate and minimize the carbon contamination effect on void swelling, two identical F/M HT9 specimens were prepared: one without a coating and the other one with a tungsten and silver coating on the surface prior to irradiation. The specimen without a coating showed carbide formation in the matrix, resulting from carbon contamination during irradiation, with no voids observed. The coated sample did not form matrix carbides, and voids were observed within the irradiated region. The same coating was applied to the ferritic HT9, and void swelling results of both the F/M HT9 and the ferritic HT9 alloys were compared after irradiation. The F/M HT9 exhibited a maximum of 2.6% swelling, while the ferritic HT9 showed a maximum of 0.8% swelling at a 400–500 nm depth, equivalent to 334 local dpa. The results were correlated with the instability of carbides in the ferritic HT9 under irradiation. Carbides in the F/M HT9 and the ferritic HT9 are both M₂₃C₆, but the matrix carbides in the ferritic HT9 were less stable under the irradiation, compared to the ones on the grain boundaries in the F/M HT9. The study shows the impact of chemistry on the void swelling which overpowers the microstructural factors such as grain size and phase.

铁素体-马氏体（F / M）HT9以及完全铁素体HT9样品在450°C下使用自离子辐照到600个每原子峰值位移（dpa）。为了研究和最小化碳污染对空隙膨胀的影响，准备了两个相同的F / M HT9标本：一个不带涂层，另一个在辐照前的表面上有钨和银涂层。没有涂层的样品在基体中显示出碳化物形成，这是由于辐照期间的碳污染所致，没有观察到空隙。涂覆的样品未形成基体碳化物，并且在照射区域内观察到空隙。将相同的涂层施加到铁素体HT9上，在辐照后比较F / M HT9和铁素体HT9合金的空溶胀结果。F / M HT9的最大膨胀率为2.6％，铁素体HT9在400-500 nm深度处最大溶胀达0.8％，相当于334局部dpa。结果与辐射下铁素体HT9中碳化物的不稳定性有关。F / M HT9和铁素体HT9中的碳化物均为M₂₃ Ç ₆在铁素体HT9，但矩阵的碳化物是不太稳定的照射下，相比于其上的F / M HT9晶界的那些。研究表明，化学作用对空隙膨胀的影响超过了微观结构因素，例如晶粒尺寸和相。