TC4钛合金低温固体稀土-硼共渗

研究了TC4钛合金在950℃低温(β转变温度以下)下进行固体稀土-硼共渗的渗层形貌、物相组成、组织性能及基体相变。结果表明,低温稀土-硼共渗,可使TC4钛合金表面获得实用的渗硼硬化层,由TiB2和TiB双相化合物组成。同1050℃高温稀土-硼共渗相比,低温渗硼层致密均匀无孔洞,而且硬度梯度和脆性得到进一步改善。低温渗硼后TC4基体为等轴组织,性能良好,能有效地防止高温(β转变温度以上)时β相形成粗晶。低温渗硼有效地改善渗层的性能,减小工件畸变。

Pack RE-boronizing of TC4 titanium alloy at lower temperature

The morphology,composed phases,properties and phases transition of the matrix of rare earth boronized layer were studied at the lower temperature of 950 ℃(under β phase transition temperature).The results show that the boronized layer consisting of TiB2 and TiB can be obtained on the surface of TC4 titanium alloys RE-boronized at lower temperature.The boronized layer is compact,uniform and less porous compared with that boronized at higher temperature of 1050 ℃(above β phase transition temperature),and the hardness profile and brittleness are improved to a certain extent become good in function.Lower-temperature boronizing can effectively prevent the formation of coarse β phase which forms above β phase transition temperature,duplex microstructure is obtained in TC4 matrix,the diffusion layer properties are improved and the work piece distortion is reduced.