Ti60合金气体保护钎焊接头组织及性能

Microstructure and properties of gas shielded brazed joints of Ti60 titanium alloy

  • 摘要: 采用Ti43Zr27Mo5Cu10Be15非晶钎料实现了Ti60合金的气体保护钎焊,利用扫描电子显微镜、能谱仪、同步热分析仪、显微硬度仪和电子万能试验机等手段研究了钎焊接头中元素的分布情况及钎焊工艺参数对接头界面组织结构及力学性能的影响,分析了钎焊温度、保温时间的变化对接头晶化的影响规律。结果表明,采用Ti43Zr27Mo5Cu10Be15非晶钎料可以实现Ti60合金的钎焊连接,在钎焊温度1 020 ℃、保温时间30 min的条件下,钎缝中发现Ti-Cu金属间化合物Ti2Cu和少量(Ti,Zr)2Cu金属间化合物。随着钎焊温度的升高或保温时间的延长,接头内元素反应越来越充分。两侧母材及钎料中的Ti元素和Zr元素相互扩散,钎缝中的组织逐渐长大并充满钎缝,接头抗拉强度先增加后降低。当钎焊温度为1 020 ℃,保温时间为30 min时,接头获得最大抗拉强度为529.6 MPa。

     

    Abstract: Gas shielded brazing of Ti60 titanium alloy was achieved by Ti43Zr27Mo5Cu10Be15 amorphous brazing filler metal. Distribution of alloy elements in brazed joints and effect of brazing parameters on microstructure and mechanical properties of brazed joints were investigated by means of scanning electron microscopy, energy dispersive spectroscopy, microhardness tester and electronic universal testing machine. Effect of change of brazing temperature and holding time on crystallization of brazed joints was analyzed. The results showed that Ti43Zr27Mo5Cu10Be15 amorphous brazing filler metal can be used to braze Ti60 alloy. Under the condition of 1 020 ℃ brazing temperature and 30 min holding time, Ti-Cu intermetallic compounds Ti2Cu and a few (Ti,Zr)2Cu intermetallic compounds were found in brazed joints. With the increase of brazing temperature or the prolongation of holding time, elements in brazed joints became more and more reactive. Ti element and Zr element in base metal on both sides and brazing filler metal were diffused with each other, and microstructure in brazed joints gradually grew and filled brazing seam, and tensile strength of brazed joints first increased and then decreased. When brazing temperature was 1 020 ℃ and holding time was 30 min, the maximum tensile strength of brazed joints was 529.6 MPa.

     

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