1. Titanium Alloy Research Center, Northwest Institute for Non-ferrous Metal Research, Xi’an 710016
2. School of Materials Science and Engineering, Northwest Polytechnical University, Xi’an 710072
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DOI:
10.7502/j.issn.1674-3962.2014.08.08
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Abstract:
The low cost Ti12LC titanium alloy was developed by Northwest Institute for Non-ferrous Metal Research to replace TC11 titanium alloy. The φ420mm Ti12LC cast ingot was forged by conventional process, and worked in φ170mm equiaxed bars finally. The equiaxed Ti12LC alloys were single and duplex solution treated separately, and then aged at 540℃for 6h. The effects of different solution processes on the morphology and mechanical properties, especially the impact toughness were analyzed. The results show that the content of primary equiaxedαphase, the plasticity and the impact toughness decreases, but the strength of the alloy increases, while the increase of solution temperature in α+βphase field for single solution + aging heat treatments in same solution cooling rate. The single solution + aging heat treatment alloys have low impact toughness, which means that the impact toughness and strength are mismatched. Compared with single solution at low temperature, pre-solution at the upperα+βphase field followed by furnace, and then re-solution treated at low temperature can resulted in larger dimension secondaryαphase, higher strength and impact toughness, while the plasticity decreases in acceptable range, the content and dimension of primaryαphase change little. The combined mechanical properties of the Ti12LC alloys heat treated by duplex solution + ageing, match well.