熱處理對(duì)SPS燒結(jié)Ti-24Nb-4Zr-8Sn合金顯微組織和力學(xué)性能的影響

熱處理對(duì)SPS燒結(jié)Ti-24Nb-4Zr-8Sn合金顯微組織和力學(xué)性能的影響Effects of heat treatment on microstructure and mechanical properties of Ti-24Nb-4Zr-8Sn alloy by spark plasma sintering

利用放電等離子燒結(jié)技術(shù)制備生物醫(yī)用Ti-24Nb-4Zr-8Sn合金，研究固溶時(shí)效處理對(duì)合金顯微組織和力學(xué)性能(強(qiáng)度、塑韌性及彈性模量)的影響。結(jié)果表明：合金經(jīng)850 ℃固溶處理后主要由β相、少量初生α相及淬火馬氏體α″相組成；在450 ℃時(shí)效處理后，合金基體β相內(nèi)析出大量細(xì)小無規(guī)則的針狀次生α相，隨著時(shí)效時(shí)間從4 h延長(zhǎng)到48 h，次生α相趨于定向析出，含量和尺寸逐漸增大；與燒結(jié)態(tài)相比，固溶時(shí)效處理后合金抗壓強(qiáng)度和彈性模量增大，而塑韌性呈先提高后降低趨勢(shì)；經(jīng)優(yōu)化后固溶時(shí)效處理制度為(850 ℃，1.5 h，WQ)+(450 ℃，4 h，F(xiàn)C)，此時(shí)合金抗壓強(qiáng)度、屈強(qiáng)比和彈性模量分別為1701 MPa、0.69 GPa和42.8 GPa。

Biomedical Ti-24Nb-4Zr-8Sn alloys were prepared by spark plasma sintering. The effects of solution-aging heat treatments on the microstructure and mechanical properties (strength, ductility and elastic modulus) of the alloys were investigated. The results show that the alloys are composed of metastable β phase, little primary α phase and α″ martensite after solution treatment at 850 ℃. After aging at 450 ℃，much short , fine and disordered needle α phases precipitated within primary β grains. With the aging time increases from 4 h to 48 h, the content and grain size of secondary α phase grows up which precipitates directionally from β matrix. Compared with the as-sintered, the compressive strength and elasticity modulus of the alloys increase after solution and aging heat treatment, while the ductility of the alloys increases at first and then decreases. After the suitable heat treatment of (850 ℃, 1.5 h, WQ)+(450 ℃, 4 h, FC), the compressive strength, yield ratio, elasticity modulus are 1701 MPa, 0.69 GPa and 42.8 GPa, respectively.

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