激光金属直接成形制备了CoCrMo体积分数分别为10%、20%、30%变化的Ti6Al4V-CoCrMo梯度材料实体件，CoCrMo体积分数为10%的组分未开裂，而20%、30%的组分开裂严重。从断口形貌、组织和残余应力三方面对开裂现象进行了深入研究。结果表明：CoCrMo体积分数为20%、30%组分的开裂是冷裂，断口呈现准解理特征，裂纹穿晶扩展。开裂的原因主要是Ti6Al4V与CoCrMo形成了有限固溶体，脆性倾向增加；随着CoCrMo含量的增加，梯度材料的组织结构发生了显著变化，析出的CoCrMo呈网状包络Ti6Al4V-CoCrMo固溶体，不仅容易出现应力集中，形成裂纹源，而且两者间热物性参数不匹配，增大了内应力。

Ti6Al4V-CoCrMo gradient multi-pass wall is fabricated by laser metal direct forming, with the CoCrMo volume fraction of 10%, 20%, 30%, respectively. The part of 10% CoCrMo volume fraction is crackles, while 20%, 30% parts crack seriously. Advanced investigations are made on the cracking of 20%, 30% CoCrMo volume fraction parts from three aspects: fracture morphology, microstructure and residual stress. The results show that the cracking of gradient material is a kind of cold cracking. The fracture displays the features of quasi-cleavage and transgranular. Reasons of the cracking mainly include of Ti6Al4V and CoCrMo form limited solid solution, increasing the brittle of the material. With the content of CoCrMo increasing, the microstructure of the Ti6Al4V-CoCrMo gradient material changes. Around the Ti6Al4V-CoCrMo limited solid solution network CoCrMo precipitated, not only the possibility of stress concentration improves, leading to crack source appearing in some cases, but also the stress due to the differences of thermal physcial parameters of two materials increases.