文章信息/Info

Title:

Microstructure and Mechanical Properties of a High-Nitrogen Core-Shell Network Structured Ti6Al4V Alloy

作者:

張波1；周宣2；董龍龍2；曹輝輝3；張于勝2

(1．西安理工大學 材料科學與工程學院，陜西 西安 710048）
(2．西北有色金屬研究院，陜西 西安 710016)
(3．太原理工大學 材料科學與工程學院，山西 太原 030024）

Author(s):

ZHANG Bo1；ZHOU Xuan2；DONG Longlong2；CAO Huihui3；ZHANG Yusheng2

(1. School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China)
(2. Northwest Institute for Nonferrous Metal Research, Xi’an 710016, China)
(3. School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024,China)

關鍵詞:

核殼結構; TC4鈦合金; 強度; 力學性能; 燒結

Keywords:

core-shell structured;  TC4;  strength;  mechanical property;  sintering

DOI:

10.7502/j.issn.1674-3962.2018.07.05

文獻標志碼:

A

摘要:

采用放電等離子燒結（SPS）技術將經過高溫滲氮處理的Ti-6Al-4V (TC4) 粉末制備成致密的核殼結構TC4。并對核殼結構TC4合金在1000°C下進行固溶處理，研究了不同速度冷卻方式以及不同溫度時效處理對核殼結構TC4合金微觀組織和力學性能的影響。利用光學顯微鏡（OM）和掃描電子顯微鏡（SEM）對核殼結構TC4合金的顯微組織和截面形貌進行分析。發現殼層具有接近單一的α相，而核心為α+β相，并且β相連續分布在α相之間，最終形成了這種新穎的核殼結構。在氮的固溶強化和核殼結構的雙重作用下，核殼結構TC4合金屈服強度達1180MPa，斷裂應變率約為10%，力學性能明顯提高。通過固溶和時效處理調節殼和核的微觀結構，可以進一步提高材料的性能。

Abstract:

Complete densified core-shell (CS) structured Ti-6Al-4V (TC4) compact was synthesized by powders nitriding and subsequent spark plasma sintering (SPS). The microstructure and mechanical properties of CS-TC4 after solution treatment and ageing were investigated. The cross-section microstructures of nitrided TC4 powder and sintered core-shell (CS) structured TC4 compact were characterized by optical microscopy (OM) and scanning electron microscope (SEM). The mechanical properties of compacts were also measured. Results show that the shell consists of near single α phase and the core is mainly composed of α laths and β lamellae. Phase transformation from (α+β) phase to a near single α phase in shell is attributed to the nitrogen diffusion, which results in such a novel CS structure. The CS -TC4 compact exhibits yield strength of about 1180 MPa and a fracture elongation of 10%. Such excellent mechanical properties should be attributed to the solid strengthening of nitrogen and the unique core-shell structure. The mechanical properties can be further enhanced through solution and aging treatment for a reasonable microstructure controlling.