基于TiH_2粉末短流程制备高性能钛的研究  

Compact Processing of High-Performance Titanium Based on Titanium Hydride Powder

作　　者：肖平安[1] 陈超[1] 曹杰义 宋建勇[1] 李志华[1] XIAO Ping＇an CHEN Chao CAO Jieyi SONG Jianyong LI Zhihua(College of Materials Science and Engineering, HunanUniversity, Changsha 410082, China.)

机构地区：[1]湖南大学材料科学与工程学院,长沙410082

出　　处：《材料研究学报》2016年第10期737-744,共8页Chinese Journal of Materials Research

基　　金：国家自然科学基金资助51074070~~

摘　　要：以极细TiH_2粉末为原料,采用压制/真空烧结的方法制备细晶或者超细晶钛,并通过HIP进一步提高钛的致密度以保障力学性能;同时还研究了添加少量Y对钛制品的影响。通过拉伸试验评价了所得钛制品的力学行为,并对显微组织和断口开展了系统分析。研究结果表明,由极细TiH_2粉末分解而来的钛粉具有优秀的烧结性能,在600~900℃发生快速致密化,当烧结温度≥1000℃时制品的相对致密度〉97%。随着烧结温度的提高,制品的晶粒逐步长大,但是在1150℃下真空烧结2 h后平均晶粒度仍然小于10 mm。拉伸试验结果表明,纯钛制品的抗拉强度在700~1032 MPa之间,而含Y钛制品的抗拉强度〉750 MPa,且延伸率为8%~10%。TiH_2分解对所获Ti粉起始晶粒度的遗传性影响和钛粉中固溶态H对晶粒合并长大的阻碍作用,是利用极细TiH_2粉末短流程制备细晶或者超细晶钛的机理。Fully densified titanium with ultrafine-grains was fabricated by the sequence of pressing and vacuum sintering followed with a hot isostatic pressing（HIP） with superfine TiH_2 powders as raw material. Then, the influence of the addition of 0.3 mass %Y on the fabrication process and properties of titanium was investigated. Simultaneously, the microstructure, mechanical properties and tensile fractured surface of titanium were systematically evaluated and analyzed. Results shows that, during heating in vacuum sintering process, the Ti powders decomposed from TiH_2 powders were born with outstanding sintering activity. For example, the rapid densification took place at 600~900℃ during the sintering process, samples with relative density higher than 97% could be obtained by 2-hour sintering above 1000℃.Noticed that the grain size of the sintered titanium increased when sintering temperature rose, however its average grain size could still remain less than 10 mm when it sintered below 1150℃. The tensile strength was in the range of 700~1032 MPa for the HIP treated Ti without yttrium, while, 750 MPa or higher along with an elongation among 8% ~10% for those with addition of 0.3% Y. It is considered that the mechanism of making fine and ultrafine grain titanium from superfine TiH_2 powders could come down to that： Firstly, decomposition of superfine TiH_2 powders granted the newly produced Ti powders with ultrafine initial grain size by inheritance. Secondly, the solid dissolved H atoms, which released during decomposition, in the Ti powders could segregate at crystal defects and thus play a role as an impediment to grain growth during sintering process.

关 键 词：金属材料 氢化钛 钛 超细晶 力学性能 

分 类 号：TG146[一般工业技术—材料科学与工程]